I am going for a sub 10 gwp gas build
First Stage

Compressors: 2 x 7600 btu 13cc r22 rotary's
HX: 20 plate brazed plate
XV: Danfoss tes2
Condensers: Unknown condenser but came from a cascade built by NoL
Refrigerant: r1270
Second Stage

Compressor: lg 13k 20cc r22 compressor
Desuperheater: 120mm finned copper condenser
XV: 1mm cap tube
EVAP: 65mm custom bartx ebap.
Refrigerant: a blend of r290 and r50