My home inspection of Speedmaster heads

Time for my own question. I measured the guides at .530 OD, so I ordered a set of Comp 518 valve seals. Old ones the seal runs down the whole bore, making it rubber lined vs the new ones that have just the seal at the stem ID.

Old ones go on nicely, new ones are slightly undersize and will not go on. I've done the usual, tapping them using a socket as a driver. Nothing.

Anyone who's replaced a seals on a set of SMs. What did seals did you use?