Depending on bodyweight 50-75mg/day for 4-6 weeks seems to be the norm. Halodrol takes a 2-3 weeks to really kick in so by the time week 4 hits, the good stuff is usually just begining and by the end of week 6 begining to taper off gain wise. I would consider starting it like this:
wk 1: 50 mg/day
wk 2-6 : 75mg day
However, if u have never used it, being conservative is always the best approach. I always abide by "make the most gains off the least amount possibe." Following this rule 4 weeks at 50 mg should still result in decent results and save some$$$$.
Hope this helps---foggia