To OP:
Good for you experimenting with different strings and tensions.
Perhaps the rest of the world knows the exact stage of your experimentation, I or other casual readers do not. You casual off hand question, contains few specifics, will only get casual general response with much guessing. For all I know, you are simply playing around and not very serious, i.e. systematic.
Depending on how you string your Kevlar string and what kind it might have different consequence pairing with low tension poly or s.g. or multi strings. I have the experience of using the same Kevlar string over multiple cross strings. The following are my recommendation:
- Read, study the "official" Kevlar, ZX thread. There are a lot of information plus both positive and positive comments.
- Tune your string bed using different cross string setup. If you string yourself, just know that it is possible to use the same Kevlar main and restring the cross to tune your string bed. This is not an acceptable main stream stringing practice. You can change cross strings and change the tension of cross string to tune the string bed. Just make sure you mount the racket securely before removing the cross strings.
- "Walking" the tension from center out is a mandatory procedure before reinstalling the cross strings. It is a common knowledge that Kevlar stretches little, but it does stretched out over use. The peculiar thing is because of this low stretch, any small segment of un tensioned Kevlar translate to huge tension lose. Plus the center mains loose tension faster then the side mains. By walking the tension, one can bring the center mains to have higher tension than the side, even if the overall main tension degraded. My understanding of the way string bed degrade is that center gets loosen over time. If you have an even tension across the string bed, it should play fairly consistently.
- Once the cross string is installed, the tension of main will come up to close to what it was. Don't worry, it will come up, although it felt like threads before installing cross strings.
- Last thing, it might still need break in period. I found that it tends to play stiff off the stringer. Age the string bed and it gets better.
My very first half set of Ashaway CrossFire ZX is still on my stick, now on sg cross. It is however "flipped", the worn center was cut, and put at the end. It still plays fairly well, thank you very much.