Hybrid builder
Two strings,one string bed.
The mains carry most of the load, take most of the deflection and are the only strings that snap back — so a hybrid is not the average of its two strings, and which one you put in the mains changes the answer more than which two you picked. Pick both and see where the bed lands.
Estimated, not measured. No hybrid combination has been tested as a bed — these figures are the two strings' own lab measurements weighted by how much of the bed each one actually is. Treat them as a guide to which way a pairing moves, never as lab data.
The classic pairing, picked from the data
A high-spin polyester in the mains behind the softest, best-holding crosses the database has. This is the setup most hybrids are trying to be: the mains supply bite and durability, the crosses give back the comfort and tension hold polyester throws away.
Which string goes in the mains?
The mains run the length of the racquet, are longer, and take the ball first. They deflect further, carry more of the impact and are the strings that slide sideways and snap back — which is where spin comes from. The crosses mostly determine how much the bed gives, and how badly the mains get sawn at the crossings.
In practice: the durable, spin-generating string goes in the mains, and the soft, comfortable, expensive one goes in the crosses. Natural gut crosses behind a polyester main is the setup a large part of the professional tour plays, and it exists because gut is too expensive and too fragile to be a full bed, while polyester is too hard on the arm to be one.
Reversing that — gut mains, poly crosses — is a real setup too, and a softer, more powerful one. It also destroys the gut faster, because the polyester crosses saw through it. The builder will show you both ways round for any pairing you pick.