RE: severne sails tack pully?
I spent some time looking for a photo of the Radz Hawaii Carbon RDM extension so I could see the horizontal spacing between the tie off point on the LH side of the plastic base cup, and the horizontal spacing of the individual pulleys (sheaves actually) and then the horizontal distance to the cleat hole on the RH side.
Unfortunately Radz Hawaii.com says they are reworking the website so I couldn't get a look at your particular base.
What I do with a 4 pulley mast base is wrap the line from the tie off point on the LH side down and around the front of the LH most sheave so that the line leads up from the rear side of that pulley (with the axle side facing you).
This takes away the funny angle that the line must follow to go from the tie off point on the front LH side of the mast base up to the LH sheave (pulley) on the tack of the sail.
So, with the line leading up from the back side (the side that faces back toward the clew of the sail) of that first pulley, there is much less "angularity" between the mast base pulley and the tack pulley in the sail.
Then the line goes up and through the LH tack sheave from back to front, then down to the middle pulley on the base from front to back,
then up through the larger dia. center tack sheave from back to front,
then down through the RH sheave on the base from front to back, then up and through the RH sheave on the tack pulley from back to front and down to the cleat.
On some bases, you get a bit of extra angularity out to the cleat, but I think it's better if any angularity ends up on one side vs pulling the tack cleat hard from both sides which can create the situation you seem to have where the line is getting "cut" by the edges of the sheave.
Another option here is to tie a large stopper knot in the ends opf your line and simply put the line down behind the LH most pulley in the base and forget about the tie off point which is sometimes well off to the LH side and forward.
Also, what size line are you using?
Most WS bases use pretty small line so it sits well down in the sheaves.
If you line is a bit larger, you increase the potential for cutting the "cover" on the braided line.
If you coulod send me a small digital photo of the pulley and cleat arrangement on you Radz Hawaii (to my email address or as a Private message here on the forums, it would be great to confirm what I'm suggesting above. It wouldn't be necessary if the Radz Hawaill site was working so I could see one of your type mast base extensions.
Hope this helps,