Fire Fly AEG rubber and buffer/nub

[Crusoe]

Has anyone got any experience of these? I know the snipers swear by them in their VSR's but what about the AEG versions?

I am thinking of putting one of these into my Real Sword SVD which uses an AEG barrel and am wondering what rubber/buffer combo to use. Options are; soft and hard (rubber) and normal hard and super hard (buffer/nub).

Gun is currently firing at 402fps with a 0.2g bb (hop set for 0.36g)

Other alternative is the prometheus versions available (buffer)

Any input appreciated- apart from "They are awesome in my VSR" which I have heard already and doesn't really help with the AEG side

Cheers
Crusoe