I'd say the 'sweet spot' for deca is at a gram.
any less than 400mg/wk is a waste, imo.
I really don't see much difference at 2g/wk.. which is what I run. (as opposed to 1g or 1.5g)
I also dont' buy into the 2:1 ratio test to deca to avoid deca dick. I don't think I've ever gotten deca dick, even at 2g/wk.. and some weeks i'll do 2g deca and 2g test enan just because I'm too lazy to shoot the other 2g or test enan.
that being said... when I 'retire', i'll probably run 200mg of test (probably undeconate) and 200mg deca per week... shit, now that I think of it.. i'll probably run 400 of each every 2 weeks. lol... when I retire, it won't be because I'm tired of using steroids and training.. it'll be because I'm sick of doing all these damn injections.