Eli is correct in his observation and recommendations.. To get 10" height
would require a lot of wood structure.. Kind of a "Trestle"..

Many boat with a mid boom sheet end up with a structure over the cabin top
and companion way.. Here was my solution, fabricated out of stainless steel.
http://hood.hctc.com/~esteve/traveller02.jpg

There are some traveler end supports that are intended to be fitted to
proprietory tracks, but IMHO they lack support in the middle of the track,
where it is needed must.

Steve
s/v Good Intentions