DIY Flooded System
 

Compressor modulation is interesting. I think it's the holy grail for some of us.

Staged multi-compressors, VFDs... I think think the Copeland Digital Scrolls are really neat for DIY. Easy to control. Just need to find one at the right price:

https://www.ebay.ca/itm/Copeland-Scr...EAAOSw6GJaAmEn

But I see it all being of limited use on a DX system. You end up with some really complicated evaporator setups with multiple TXVs and solenoids.

Who's going to build a great big shell-and-tube flooded evaporator, with low side float control? You could 0 to 100% that bad boy all day long.