Scot,
I raised the boom by 14 inches (I am tall) and it did change the angle of the forestay but it doesn"t seem to make any differance. The boat has a little more heal but not much and it is ok. If you raise the boom by raising the mast you will have to lengthen the shrouds and forestay as well. I have made a lot of mods. to the boat and this is one of the best ones. I really like not having to duck all the time. Good luck and if you make the change let us know how it worked out.