Dave,
Welcome. I’m not sure if your question was directed to me, but it seem to be so that’s how I will answer it. I hope I don’t come off sounding grandiose.
Yes, I used a rifle length buffer spring in a carbine buffer tube. I also used a variable weight carbine buffer for my set ups. PSA uses an AR-10 buffer spring and a H2 (I believe) buffer. I found this set up to dramatically ease the amount of strength it takes to charge the weapon after a mag change.
As to any other pointers check this thread
and this one
Why the KS-47 BCG is different - PSA Products / KS-47 - Palmetto State Armory | Forum
I have a 10.5" PSA factory that I added a Devil Dog Concepts Hard Charger side charging handle to and a 16" which combines a PSA lower, a Gibbz Arms G47 side charging upper, and a barrel and furniture from a BCA 7.62x39 AR.
Any questions just ask, the folks here are awesome and aways willing to offer help and advise.