Personally, I LOVE fina only. That is because I get zero sides, and only put on a couple of LB's (and I dont want anymore size). that said..
The consensus is that you need to throw in some test with it, because alot of users experience fina dick (no more hardon), and fina will shutdown your natural test production. The first couple times I threw in some proviron to combat this (and I liked prov...seemed to only add to the muscle hardness), but the last few I have done strictly fina only with no problems. In fact I get an increased libido, and for some reasons keep making strength gains in the gym for approx 3 weeks after discontinuing use (I have to admit, this stumps me).
So anyway, If you are gonna do fina only, and arent very experienced user, I'd go with about 50mg ED for 8-10 weeks (most will say 8 weeks)If you are more experienced id up it to 75mg ED. If you decide to add it with some test, I'd listen to someone like mr.X or other experienced guys....I just havent done enough test/tren cycles to KNOW.
good luck