Most racquetball racquets have much longer main strings, than the shorter cross strings.
It is usually better to have them strung at different tensions
String Tension for Racquetball
Whatever racquet sport you play, there is usually a recommended string tension shown on the racquet.
This is not always the case with racquetball racquets, in which case you will need some advice.
The tension of the strings is one of personal preference. There is no ideal tension suitable for everyone.
You will have to experiment until you find the combination of string and tension that provides you with the best performance.
Recommended String Tension
The recommended tension for racquetball racquets is normally between 30 to 40 pounds
You can also check the racquet companies website. They sometimes (but not always) have a section dealing with stringing instructions