Just a feeler this......
As to macro quality, you could try buying an F series AF adapter and marrying it up to an A series 100mm macro. It gives you a stunning 170mm AF ! It would probably be cheaper than what you are proposing?
Both the *istDS and the K5 are incurably addicted to old glass
My page on Photocrowd - link
Can't imagine a DA*200 being much lighter than the DA*60-250.
Z-1p, K-1, P50
F50 1.7. FAs 24, 35, 50 1.4, 85, 135

Metz 45 CL-4, AF500FTZ. AF540FGZ.
Some Mamiya and some Nikon
Alternatively an FA or DFA macro with the DA1.4x. Gives you a 140mm f4 equivalent.
Can't imagine a DA*200 being much lighter than the DA*60-250.
Yes you are quite right - I've just found the weight of the two lenses. The 200 is 915gm (2lb) and the 60-250 is 1240gm (approx. 2.5lbs. Add a couple of pounds for a K3 and you have enough weight to pull an oldie off-balance when trying to lean into a flowerbed....
I cannot run to the Pentax 1.4 but I have found a Kenko AF1.4x sitting in the back of the cupboard so I'll give that a try. (Is'nt Kenko a coffee company?)
Just passing thru
Kenco is the coffee company...

Z-1p, K-1, P50
F50 1.7. FAs 24, 35, 50 1.4, 85, 135

Metz 45 CL-4, AF500FTZ. AF540FGZ.
Some Mamiya and some Nikon
cbrog
Plus Member
Surrey
Roger