I have never heard cutting T3 off 10 days before a compatition and don't really see the logic in that either. T3 is something I would continue to run to almost a month after the comp to tapper it as well as help avoid any rebound.
As for dosage start 25 mcg first week 2nd week 50mcg 3rd week 75 mcg. I wouldn't run it above 75 mcg. After the comp bring it back down to 50mcg for 2-3 weeks then 25 mcg for a week.
As for Winny that is not my first choice for cycle in fact it comes in dead last as choices for a cycle. Have you ran winny before?