Better method of central sheeting i have seen was on some of the Euro A-Cats. Normal blocks on the traveller, but the sheet would run the entire length of the boom to the mast, before coming back to the centre under the tramp and exit that way.

Premiss was that when pulling on the sheet you were only adjusting the sheet and not pulling the traveller up the track. And by having it running from the front beam to the centre under the tramp, wouldn't catch it if you were tacking/gybing.