I use 30lb felt, never tried Tyvek. I can tell you as we reside the
house, some of the old was 30lb some 15lb, the 30 is still doing a good
job after 50+ years, the 15 is dust. I question applying over the old.
won't that make some problems with the trim around doors and windows
due the additional thickness? That wasn't even a consideration on our
job, as I wanted to do a lot of electrical and plumbing while the skin
was off, and it gives you a chance to spot decaying 2 X 4s and replace
them.