Although disagreeing with Omega will make a short career (dude has a lot of knowledge) I have never personally found injecting slowly to help with post injection soreness, just the tren cough.
I been injecting HCG (water) and tren+prop in one shot. Only doner it twice, the last injection site is more painfull than normal and feels like a lump
pretty safe bet that the winny was in water - the only kind I've ever seen in oil was oral and full of huge crystals. Either way I've heard of micrnized winny but it's usually to big to flow through a 25 gage. First cycle I ever had I tried that and it kept jamming in the needle.