edit: i personally would recommend the following settings for HD encodes after this test:
edit2: changed GB/GBC: 8x8 is big enough to get full HD
#GB/GBC:
PointResize(1280,1152) # 8x8
#GBA:
PointResize(1920,1280) # 8x8
#NTSC NES, SNES (256x224)
PointResize(2048,1792) # 8x8, must force 4:3 on youtube
#NTSC Gens (320x224 dominant) must force 4:3 on youtube
#320x224 sections:
PointResize(2560,1792) # 8x8
#256x224 sections:
PointResize(2560,1792,32,0,256,224) # 10x8
#NTSC Gens (256x224 dominant) must force 4:3 on youtube
#320x224 sections:
PointResize(1024,896).PointResize(2048,1792) # 6.4x8
#256x224 sections:
PointResize(2048,1792,32,0,256,224) #8x8
#psx: too may possibilities, and too complex to list here. the method also doesn't even work for many psx resolutions (in particular, if the normal encode is 240 high)
#arcade systems: not well standardized enough, so just BS something that looks good enough
#other systems: i haven't researched..