I hit a SW forehand and a Continental/Eastern backhand. I'm comfortable with the depth on my forehand, which I with a lot of spin, but I think my backhand-which I hit flat and about a foot or less over the net- could use more depth. What could I focus on so that I can get more consistent depth with my backhand?
I use Gamma Durablast at 50 lbs if that's of any relevance.
A foot or less net clearance hitting baseline-to-baseline? The answer is NOT to hit harder. You are trying to hit a frozen rope backhand and you are not giving yourself any room for error. Slow down your swing and go for more net clearance. Dial it back the power a bit and hit 3-4 feet over the net. Yes, you can keep that ball in the court. If not, then swing slower, or the better option is to add topspin.
The only way to develop consistency is to put in the work on the practice court. It doesn't just happen. Since it sounds like yo uare still trying to figure out your backhand spend some time with the ball machine or feeds, and then when you have something to work with you need to find a partner and rally. Try hitting 20 in a row past the service line (not hard at all, that's only 10 each!). When you hit 20, stop and start over and go for a 50 balls in a row.
Oh, and your string and tension is of zero relevance.