That test is unlikeky to tell you anythibg useful about the battery quality.. If anything it might tell you how they are stored/abused. And storage/use/abuse is likelyvthe thing to worry about with SLA batteries,... they often get killed more than dying of old age.

Buy a good brand name SLA battery from a trusted/high volume dealer so it hopefully has a fresh manufacturing date and should arrive with a decent charge on it. Fully charge and then discharge test and write that date and tested current/capacity on the battery and repeat at every annual. The West Mountain Radio Computerized Battery Tester is a great investment, especially for clubs, FBOs, A&Ps etc. . When capacity gets to about 80% of spec (not initial measured capacity, which is likely higher) I would replace.

You may be better off using LiFePO4 batteries.