IMO, tren isn't a great drug for gaining a lot of muscle. It's a hardening drug. Sure, it is strong and you can gain on it (just like any steroid with the right training and diet), but overall, I wouldn't call it a big gains drug. The gains you will make are less likely to be water though and you'll probably lose a little fat in the process as well. 75mg EOD should have been enough to get a decent effect. If you weren't making gains on that, I'd consider looking at the diet. 75-100mg EOD is a pretty standard dose for ace.
As for dosing tren e, 400mg EW should be plenty. The idea of running low test with it is a very new school idea. I have not tried it, mainly because I like test too much. Even at a 1 to 1 ratio, I suffer some mild effects on libido from time to time. I usually run more test than I do tren and the gains have always been good for me. 5-600mg test EW would be enough test, based off of the expereince you've talked about here.
On a side note, Be aware that with the longer ester, tren sides can be worse, as the hormone builds.
Cycle would look like this. If you are cutting, you could throw in something like winstrol for the last several wks.
1-12
Test E 5-600mg EW
Tren E 400mg EW
adex .5mg 2x wk to EOD, as needed
9-12
Winstrol oral 50mg ED