The Turbo Grip Strips 3/4" are inserted into the thumb and finger holes to help adjust fit due to shrinking and swelling. The strips have a unique textured surface to enhance the grip of your bowling ball
Is it round end up, and where do you place in thumb hole?
The round end of the tape goes down in the hole while the flat side will be even with the top edge of the hole. Because this tape is textured to enhance your grip, you would position this in the hole so your thumb is gripping it on the "palm side" rather than the back side of your thumb.
Do the different colors have different textures from one another?
Is this the most "gripping" tape you have? If not, which of the tapes you sell is?
The Grip Strips will all have the same grip but there are some types of tapes that will have different thickness and different types of grip. It is hard to say which is the most but if you check the fitting tapes there are some that mention in the description which color has the most grip.