FWIW......If it's any consolation at all......we have sold literally dozens of these boot kits....and as of yet, we have not had any calls back from customers saying they had issues with the boots splitting.....
The biggest thing is to fill with just enough grease and to get most of the air out when sealing it up. In Whiskey, some is good, more is Better. But not in grease. So many wheelbearing caps STUFFED full only to push out the excess.
If there is not an gross amount of driveshaft angle miss-match the boot should not split.
YMMV!