anyone heard of it?
Yes, there is oil based winny. Some people prefer it over the water based because it is easier to controll bacteria...water based winny and test-susp are often linked to infection. As far as if it's a better form of winny, I'm not sure about that, I've heard that being mixed with oil instead of water that this can compromise the strength...I don't know if there is any validity to this or not.
As far as winny being used in a bulking cycle as mentioned earlier, it is more suited for a cutting cycle, but I have used it at the end of bulking cycles before. Doing this can help solidify gains, but it is not necessary.
BTW, 10% bf is not fat, anyone who thinks or says it is is retarded.