I think one could gain 10lb of lbm in 3 weeks with a 2 week cycle. Start bulking on day one and go on bulking for 21 days. 'm sceptic if the 30mg dbol will do much in that short time. It took me 1½ weeks to feel 30mg and next time I upopoed the dose to 50mg and It kicked in by day 4, so you might want to up on the dose the first week.
Maybe something like this:
300mg prop day 1
100mg prop days 2-14
Dbol 40-50mg day 1-7
Dbol 30mg day 8-14
I also would count in proviron at 50mg as an anti-e, or if you are very sensitive, 0.5mg asrimidex EOD. Up on the protein to 2 - 2.5g per lb BW. Don't overdo the workout in the gym, this will only make you burn more cals = have to eat more. 1-1-1 or 2-1-2 would be nice.
I also would eat more high carbs during the day and lower GI at night.
I'm going tp start a 2 weeker in 2 months or so. I will start the real BULK after about 4 days from the start. I will also include creatine 25g per day, alpha lipoic acid to every carb meal, and I will take one week OFF from all training in week 4, think the body will need it. I will cycle like this: Prop 300mg day 1, then 150mg EOD for 14 days. also 150mg Tren day 1, then 75mg ED, and dbol, proviron and arimidex. I will start clen during week 3 to keep more ggains but still eat the same this week and to get more benefits from the stuff that is still in your system.