Ahhh okay, thanks for that info. Maybe it doesn’t matter so much then whether it is top or side mount.If the wallet allows I'd recommend go with a cartridge filter the biggest you can $$ and fit in the spot. The plumbing is secondary as I believe do it once and enjoy forever. By the way the DE addition to a sand filter is via the pool skimmer and has nothing to do with side or top mount mpv.
You’re the second person to recommend the cartridge filters to me. I don’t hate the idea but they do seem rather expensive and a pain to clean although I need to do more reading about the pros and cons. For reference, I am dealing with a ton of algae and need to do a SLAM soon. I am just waiting on my test kit to begin the slam so I’m not doing it blind. Also trying to figure out how exactly to clean it while my filter is out of commission. Seems like I’ll be doing a lot of manual skimming, vacuuming to waste and recirculating.