Just depends on depth. I watch my screen to see when I’m getting too many wave returns. I always have it tilted slightly at those depth. I’d say 5-10 degrees nose down if I was guessing. Turn down the gain quite a bit and play with the angle, I’d bet you’ll be pleasantly surprised.
Sorry, it a great answer I know.
And if fish are at say 10 foot depth in 30 FOW, I’ll tilt it a bit more to see the most fish. With my PVC pole on a RAM mount I can play with the angle with it deployed to get the best picture. Then I can adjust the transducer mount up or down as needed to keep the pole level.

