Actually, the sub-max weights will be slightly more effective while on Superdrol... But anyway, the point is for you to be able to maintain your weights used or even increase them after you come off, so you can keep your gains. As long as you can do that, then you should be fine. I think that is the fatal error most guys make - dropping the weights after they come off. You should be dropping the volume, not the weight, as you come off.
Re: Dbol only - I know a couple people who got big off of Dbol, and a lot of the pros in the past used only Dbol or only Dbol and test, so... they didn't even do PCT back then, but I bet you a ton that they at least maintained the weights they were using and kept eating like mad.