as for the Dbol, I'm a huge fan . I run Dbol all the time just as a pre-workout (keep in mind though I'm on TRT and don't ever have to worry about natty recovery or pct) , I also know how to dial in estrogen sides pretty good, I run an standard AI like arimidex on cycle, but when I blast some Dbols here there I will often times add some Letro in the mix to keep estro down even more.
as for mixing compounds in one syringe, thats all dependent on your dosing protocol . Personally I prefer more frequent injections (even daily), I'll mix 100mg of tren, with 25mg of test, and 200mg of masteron, for example, and inject that EOD in one syringe. Or I will back fill slin pins with different compounds that I'm using and inject those every day in different spots (chest, bicep, thigh, etc.)
its all dependent on your dosing those first,, once you get the MG's all figured out and how much cc of each you'll need, you can come up with a dosing protocol and mixing them
i wouldn't do anything with the winny at this point. save it for a cycle way down the road where you want to cut and dry out at the end , or maybe a quick strength boost at the beginning of a cycle