it all depends on the person taking it. Everyone is different and everyone gets different results. One thing is for sure it will be fun watching your body change, and peoples reaction.
I gained around 10 lbs while losing BF in 6-7 weeks,so it certainly can pack on the mass in high enough dosages with the right nutritional factors in place.
50mgs/day of BTG Oxandrin.Calories were not changed real dramatically,with the exception of protein.I consumed at least 2 grams per lb of BW daily.No creatine was used.