I have been hitting with a 16x18. I just switched to a 16x20 frame with almost identical specs (Yonex vcore 95d) and found that my forehands were a lot lower over the next, or went into the net. Whereas with the 16x18 they landed deep. I assume this is the string pattern causing this. I strung my 16x18 with gut/poly at 52/50. Tried the same in the yonex. Should i drop the tension to say 52/48 to increase the launch angle?