I have always used Velox tape. I never tried "layering" things since I never had an issue with Velox and, I think the less room you have in the rim "channel" the more difficult it might be to mount very tight tires. It was a chore getting my 18c Vittoria tires with Kevlar bead on my Mavic rims even with just one layer of Velox, but a normal chore.