I have never bought a rigged T4.9 mast only blanks.
I know there are masts with the top only sealed. That is sealed from the top to the hounds.
(I can't say is this is done by the owners or AHPC)
Below the hounds the "T" ball diamond fitting makes it a bit suss to seal the whole mast.
I don't use the "T" ball sysytem and seal the lot.
Having said that, it is not really neccessary to seal the lot, as the mast is so bouyant with only the top part sealed it rarely takes on much water through the "T" ball fitting.
As far as righting goes. I use 8mm silver rope as it does not absorb water. The rope goes from the front beam where it meets the gunwale in a "V" held up by shock chord to the other side , same position. I have a knot every 12 inches. When I tip I wrap the rope at a knot twice around my trap hook which fres my hands to hold out over my head to get more weight out. As the hull moves up I can bring my hands in, and pulled the rope tru to the next knot and so on.
Works for me.
Hope it helps.
Phill