BB is always a game of expanding and contracting. When you diet down, you can't help but lose some size. The thing you can work on during your "losing size" phase, is staying full. It takes the right balance of carbs and fats, to maintain some level of fullness. This may be the issue that concerns you. When you go flat, you lack that certain "pop" that makes a physique impressive. There is always a scarifice when dieting and you can never always look full, but you should be able to maintain fullness to an extent, some of the time. I would play with your fats. They can allow you to look more full without having an effect on insulin. Of course, too much and you will blunt fat loss. Just remember that you are never going to look as full as you do in the off season. A lot of guys, pros included, don't look that impressive in clothes, by the time they are dieted down. If you want to be ripped, you aren't going to be bloated and full of intracellular fluid.
As for your gear dosing, I'm not fond of setting up a cutting cycle with more compounds toward the front of the cycle. As you are seeing, you expereince a strong build of hormones, and then a dip toward the end. I'd prefer to have run the test 500mg and EQ 600mg, through the whole cycle, then in the last 8 wks, add tren. Last 6 wks, add masteron. This way, the hormones are constantly building. Upping your test to 750mg will work for this run, but I don't think it is ideal.
As for cardio, I can't say how much you need, not knowing how you look or seeing your diet, but to get really lean, most guys I work with slowly increase their cardio, doing up to 7 days a wk by the end, sometimes 2 sessions a day.