NSW
1511 posts
I suppose it depends on the age of the sail (all my sails are old).
I have success with the loop and go threading on the XT base using RRD(FireWing), Simmer (2XC), Sailworks(NCX) and KA(koncept).
Some have needed a groove inserted on the middle pulley(not used) just for threading as sometimes the centre pulley is bigger.
Good Luck