I ordered a 4.5 needle head set kit from H&S to upgrade the tip of my 24'Ultra. Everything fit and there is an improvement in ease of cleaning of tip dry with the new head. If in the future, if I buy the H&S evolution I will purchase the the single needle version with the 2.8 mm head set.
.I also ordered the the needle tip kits in the Pro line of Badger Patriot upgrades. I purchase the extra fine,fine and medium tip/needle kits. These all fit and performed as expected. Badger is much more manageable to tune up, in price, as compared to H&S.
Overall you get more bang for your buck with Badger vs H&S. The finish is nicer on the H&S. Badger is more versatile than the Ultra. Both deliver good spray patterns and final finishes.