Hi puppet ..yeah keep the same brand ..for the same mast flex...go for the NP 430 .mast to start ..boom 160-210 should cover all your sails .
5.0 ,6.0 7.0 ...or close ...if you only want 3 sails ..
if you go below ..say 5.5 you will have to get a 400 mast unless it has a top strap .
i have 4.2'. 5.0'. 5.8, 6.3, 7.0
just to give some idea..
you probably won't need a 4.2
as 146 litre board would get blown out of the water at 30 knots.
go a new boom ..if you can .as they take all your weight ..and you do keep them a long time .
tardy