The only person, afaik, who made seam guides for the various Poser figures and some of the Genesis iterations is SnowSultan. These being actual SEAM guides rather than standard UV templates. Unfortunately it appears that she stopped making them before LF/LH came along.

Here is the drive link to SnowSultan's archived templates...

https://snowsultan.artstation.com/pages/seamguides

3Dream made some templates for LF/LH, I assume they are color coded by mat region, as his templates usually are, going by memory.

https://www.sharecg.com/v/95553/browse/11/Poser/La-Femme-+-LHomme-High-Resolution-Templates

The templates for LF/LH I have aren't color coded, if I remember correctly they were included with textures of original distribution. I might be mistaken. I may have generated my own using Mudbox (I usually use Mudbox for templates as it generates a layered PSD, with template, per UDIM uv tile while 3d painting. UVMapper Classic gets befuddled by UDIMs. In other words 'out of range UV data' warning... Unless you process LF/LH UVs via this freebie, which converts the UDIMs to legacy style stack single tile.

https://www.renderosity.com/freestuff/items/81125/la-femme-no-udim-uvs-for-uv-mapper-pro

I believe this load uvs file process works also in free UVMapper Classic via the file dialogue. I recall generating stacked with the UVs file in Classic years ago. Of course then you have to separate everything to generate the relevant image file exports. A lot of selecting, dragging, scaling.

In any case I've recently purchased RizomUV software. I can't recommend this enough for UVing tasks... Seriously, I'm shocked how it unwraps things in a snap that I used to struggle to flatten out in Wings with tons of cutting, pinning, unwrapping, and stitching. It's almost like sorcery how well it works. Just a beautiful piece of software. And UDIM tiles with a button push.

But I digress. As far as how difficult it would be to create fishnet stockings for LF? I can't say. It would probably be actually easier to do it the old 2d image editor way rather than trying projection painting in 3d painting. I imagine you'd have to fuss alot with fixing overspray distortions in pattern as you turn curves. A bit of strategic stocking seam placement in your image editor, LF's leg seams run along the inside of the thigh (shown here as a red paint stroke on the model as relates to UV view)...