Neilpryde Boom Head question

I bought an X9 Neil Pryde carbon boom a couple of years ago. In my naivety I didn't really know what I was looking at and bought it as is. I used it initially and thought I was doing something wrong but the boom to mast connection always felt sloppy. I hardly used it last season and went back to using an alloy chinook. I know now it should have a shim for at least a rdm mast but it was never any good on the standard either. So the question is what am I missing to use this with both a RDM and SDM? Or should I take it off and replace with something else? I have searched around a bit and streamlined looks like it should be versatile enough but looks to be out of stock, it also looks expensive no price listed at Surf Sail... Any tips greatly appreciated.

Thanks Tony that went some way to resolving the issue with the RDM mast . I ended up seeing Reg at WSP who I showed the boom to, he had that shim but he had a closer look and in his opinion on the lever arm the cleat wasn't quite in good enough shape to keep the rope completely secure, so bought one of those as well, lo and behold I now have a good boom to mast connection can't wait to test it

I have a few of these booms and the two part plastic moulding that sits against the mast (front side of mast) is poorly designed and breaks down, I think its the co moulding one part being black the other blue/green/orange or yellow in your case depending on the year of the boom. Awesome booms, but watch this like a hawlk as they break down suddenly and leave the inner hard plastic ribs rubbing against your nice expensive carbon mast. The shim helps for RDM but the issue is with sdm. The shims break down as well. I now need three replacement heads for X9s if anyone has one to sell.

Brings me back to this query from the initial post. what experience has anyone had with these? Is it compatible with most booms? Cost? as it just listed as sold out on Surf Sail Aus, and are they still available from somewhere?