Synthroid is approximately 1/3 the potentcy of T3, so you can research T3 for dosing variations and ideas, then simply multiply the dose by 3 (maybe just a bit over). Yes tapering is a good idea with thryoid homone so that your body will become accustomed to it, and sides will be lessened. I get good effects with about 100mcg-150mcg tops. IMO thyroid hormone should be kept to the absolute minimum effective level because of all the sides that come with higher doses (muscle loss, dizzyness, fluctuating metabolism, did I say muscle loss?). Start with 50 and up it 25mcg EOD untill you are at a comfortable level (getting results), then level and cruise at that dose untill you are ready to taper off. Thyroid shouldn't be used for extended periods of time, as the loss of your natural thyroid can be devastating, especially for someone who is overweight to begin with. Maybe one month tops, before a break is needed. You can of course use it again after a proper off period of about the same duration if desired.
As for the proviron, I don't know where you think that needles figure into that equation as all proviron, with possibly the exception of some homemade product, comes in pill/oral form. I would not use this unless you plan to run a cycle with the synthroid, as proviron is technically a steroid and will shut down you HPTA as such. Regarding the cycle, that should really only be considered if you are considerably above your natural genetic muscle mass. From the sound of your post, I don't think that you are. Instead of proviron, you might try some clen and ECA to cycle 2 weeks each during your cutting diet - this will be much more effective than proviron. Proviron will only really have any noticeable effect when BF levels are very low so the hardness can be seen underneath the fat, much like winstrol or masteron.
Remember to focus on the most important aspects the most, which of course are diet and exercise, and think of the drugs/supps as merely an afterthought to boost the results you would already be getting through your hard work. Remember, their is no easy way out, but you will be pleased with what changes when you put in the work!
