I've never owned the WR flash units.. would have liked to but they were too pricey.
I have however always had access to ziplock bags and rubber bands. and still do..
lately I have found litro lite cubes videolights to be my go to source for all weather lighting outdoors

that's the answer I was looking for. thank you.
the good news is your old pentax flashes all still handle A and M modes so are not completely useless...
the good news is... the wistro 200 absolutely KILLS the pentax system... for the price of an older 360 fgz flash you can get the 350 p AND ad200 and you got controller(working as fill or catchlight ) and a powerful key light with full ttl and hss!!!

thank you for that... the lil tt350 s on my sony acts just like a sony flash on it's own, so there's some reason to hop the pentax version of that flash will have all the feature of the pentax system PLUS the Godox wireless features... as the sony version on it's own does ttl just fine and it's tiny size makes it a must have as a standalone flash and as an access/hair or catchlight when used with multi flash...

on the sony system.. you can use EITHER the radio transmitter or a sony dedicated Godox flash unit (I have the adorable little TT350s) and it will fire the other flash units.
The transmitter allows you to set groups and channels and control each unit or group from the camera eg you can set to manual auto or ttl from the camera... so

the big question I'd have is does the transmitter/flash send out a P-ttl optical burst that would also trigger the p-ttl flash units from Pentax or is it all Godox radio signal and proprietary? I can't test this without buying the Pentax dedicated Godox radio transmitter.
all current Godox flashes have a radio receiver and transmitter built in including the little tt350s I bought... they packed EVERYTHING the fgz 360 had plus radio control into that tiny flash... I'm amazed.
correction there is a pentax version of the tt350 online...

that means in simplest terms you'd need EITHER the transmitter OR a dedicated Godox flash to fire other Godox flashes and still no idea if you can use the Goddox system to fire Pentax flash units with wireless P-ttl...

before going the ad600 route there's 2 other options worth considering...
the 400 is way cheaper than the 600...
and also there a dual ad200 adapter that let's you plug two ad200 together and use them as a 400...

my plan is to use the 400pro and dual ad200's to make a three light kit that can be used as TWO 400's or one 400 and two 200's for multlight setups.

I bought into the godox system when I switched to Sony...
I have the wistro 200 and Elinchrom adapter, and one smaller shoe mount flash for the a7iii .
I am ordering the 400 pro with Elinchrom adapter... soon...

So quick question before I order the Pentax trigger...

Anybody using this system yet? have you had any luck combining p-ttl Pentax flash units with the Godox system units?

please do share your tips and ideas and experiences?

while it broke my heart to switch to sony, I still intend to use my old pentax stuff until it dies.

your point about the cost of the processor is valid, powerful doesn't need be expensive, but.. those amd multicore processors ARE POWERFUL... and that is what the software runs best on... Photoshop likes ram 32 gigs is the sweet spot, fast multicore (6 cores is the sweetspot) processors and for some effects and plug ins cuda cores on Nvidia graphics cards... hence my comment earlier about not really needing to spend on an upgraded amd graphics card unless you want to edit video.... a full version of photoshop is coming for the iPad Pro , which is touted as having a processor that rivals the Intels in the Macs on some benchmarks it's a powerhouse processor...

that guy's an idiot... buy somewhere else.

The new iPad Pro looks promising..
as far as photoshop is concerned any new Mac will do the job. but...
the real issue is workflow....
you have external monitor, if you also have external raid hard drive and an external ssd drive then what you want to look for is any Mac with a thunderbolt 3 port.
in your shoes based on what your original post said, I'd opt for the following setup...

buy the mid tier Mac mini, pay for the upgraded processor, do not pay for ram upgrade, buy that separately and upgrade it yourself or pay a friend/shop to install the ram.. at least 16 gigs of ram, 32 is better.

then... plug in ONE Usb3 gen 2 or thunderbolt 3 ssd drive of at least 1 TB capacity and set it up as your scratch disk.

add a usb-c external raid enclosure with a raid 0 setup and at least 2 2-4tb drives.

add a usb3 backup drive with enough capacity to back up ALL your drives.

run photoshop off your computers internal drive BUT use the ssd for a scratch disc and use external storage for your photo library, and to quote Chris Farley "For the love of GOD!!!" make regular backups.

lastly..

look at a thunderbolt 3 egpu (HP omen is the cheapest, razor core is good so are sonnet and akidio) and amd radon 580 or better graphics card... if you want to speed things up a bit for gaming or video editing at some point in the future.
link

I mixed new and old flashguns all the time.
the only reliable methods were everything on manual, or mixing manual and "auto" (no ttl or p-ttl) using optical slaves and or radio slaves and had no issues mixing old vivitar 283's, 285's, 2800's with newer strobes and studio lighting... but always on "A" settings or full manual.. I didn't have to worry about voltages or anything else on the old viv's because I primarily used them with optical wein peanut slaves... or voltage safe hot shoe adapters connected to Elinchrom radio slaves. on camera either the elincrome transmitter or a modern flash set to a or manual.

a flashmeter is the best tool to have if you go that route