Hobie 18 - tuning and checking

Hi Guys and girls

I have a old Hobie 18 and I am trying to start tuning it up to get the best out of her. First question is mast angle, I was told that the top of the mast should be over the centre of the tramp is this right? The reason I ask is that I am getting weather helm but the rudders look ok.

Also looking at some of the posts here there seem to be some know problems / mods to do on some boats does anyone have a list of things to check and so on. Not evensure how old she is but has a 14000 sail number?

Any help gratefully accepted

Thanks

Ian