I would try to return/exchange the shafts (if you have not done any cutting yet) for a 'R' flex set of shafts. There will be a significant amount of tip trimming that will need to be done, which can present a problem for your longer clubs, if your shafts will even allow for that.

If you do decide to stick with these, heed Ben's advice. Also, the butt diameter should still be .580 or .600, depending on the shafts, so building up the butt would not be required.