You just need to tell the actual bore size (not piston size), and the ring thickness. They've done Opels for me many times. FWIW, I would just order a standard Hastings (chrome) full ring set, and order the gapless second ring set from Total Seal. It will save a lot of money compared to getting the entire Total Seal set, and you gain the benefits of the gapless rings still. You just won't use the Hastings second compression rings. The Opel ring thickness' are 2.0 mm, 2.0 mm, and 5.0 mm (from top compression ring to bottom oil ring).
You WILL need oversize rings if you bore the block out and install new oversized pistons. You should not need any +.005" rings unless you simply desire to file-fit them by hand. Even a loose-fit gapless ring will seal better than a new standard ring that's file-fit. The option is yours. BTW, make sure when you freshen the shortblock that the head is done at the same time. The Total Seals will pull so much extra vacuum that you will develop oil blow-by problems if you have worn valve guides and valve seals.
Bob
You WILL need oversize rings if you bore the block out and install new oversized pistons. You should not need any +.005" rings unless you simply desire to file-fit them by hand. Even a loose-fit gapless ring will seal better than a new standard ring that's file-fit. The option is yours. BTW, make sure when you freshen the shortblock that the head is done at the same time. The Total Seals will pull so much extra vacuum that you will develop oil blow-by problems if you have worn valve guides and valve seals.
Bob