I do quite a bit of flash work with the flashes off camera. I don't have any experience of any Godox products, so was unable to respond to your original question. you will do better asking on PentaxForums.

if your post today was meant to show displeasure, remember that communication is a two way street https://www.pentaxuser.com/forum/topic/flash-in-lv-62191

You are very welcome.

Had a quick play in LR

The padlock when locked constrains the aspect ratio. So you can grab the corners of the crop frame and move them but the aspect ratio is unchanged.

When unlocked you can use a custom ratio.

If you want a 10x8 inch image select that in the crop tool and frame your picture. Then click export and in the image sizing dialogue box select "resize to fit"; change the width and height to 10 x 8 inches and select 300 ppi. You will get a correctly re sampled image of 3000x2400 pixels.

If you want a different aspect ratio from 10x8 then dont use the 10x8 crop tool. Use the crop aspect ratio that you intend to print at.

20” x 16” at 300 ppi means your image file should be 6000 x 4800 pixels

Just multiply the ppi by the print dimensions

That is only part of the equation. For a print you need to multiply the physical size by the ppi to give you the pixel dimensions (resolution) you need.

Many printers will, but you will get better results by preparing your file yourself rather than allowing a printing company to downsize/upsize your image.

DS Colour Labs who I recommend in this thread require 300 ppi. Knowing that, and the size that you want to print at, gives you the resolution you need in pixels.

Nice action shot.

i like no. 3 for the simplicity and lovely saturated greens.

Nice work.

Not a safe option at all if the lab wants 300 ppi.