<<Regular GEO maps with arid environmental conditions? >> This is how I played it back in the day and it worked reasonably well. If I were to do it again, I think for any 3 board setup I'd replace one 'standard' board with one desert board having d3+2 desert overlays placed per F12.3. Be a little careful here since various arid conditions rules kick in with different levels of desert board usage. (The tables in the attached chart with titles in green are always in use in arid climes, the ones with titles in red are only if 1+ desert boards are in play, hopefully this helps.) You might also think about randomly replacing standard features on normal boards with arid equivalents via replacement dr (e.g. on a 1-2 all hedges on the diced for board become cactus hedges, etc.)
I'd also be tempted to mix in a couple 1st line squads with my initial force (maybe dice for each squad and replace with 1st line on a 1-2?) but that's just me.
This is welcome news about the arid boards dump with LFT 15! It's a terrain style sorely lacking so far. Not just for North Africa/Med but also parts of Manchuria, if the Chinese & Korean films I've seen are anything to go by.