The only correct way to tighten up older Waves is to replace the plierhead and the plierhead pivots.
Just tightening the 5 pointed Torx screws will leave you with very hard to open blades, without attacking the real problem which is wear.
I've stopped replacing parts on old Waves altogether, when these come in and the customer hasn't stated a certain fondness of the old tool, it gets exchanged for a New Wave.