What kind of guide are you looking for—print sizing for glass and stainless-steel tumblers? If so, the best approach is to measure your own tumbler’s circumference and height to get the ideal dimensions for your design (Keep in mind: not all tumblers are sized the same—different brands often have slightly different measurements).
If you’re looking for heat press settings, I’ve got a great resource for you right here: HTVRont Auto Tumbler Heat Press - #2 by Jodie