Single handed? Aboat a 5-8 ton boat should be the right size for a single person doing that voyage. Look at an open 50 or an open 60. I hear someone even circumnavigated single handed in one of these!
BTW, you are already a proficient sailor with offshore experience before your considering making these trecks right?
(you know, there are times I know that someone with my level of (in)experience REALY shouldnt mock, and I dont blame the guy, but this is the third one today)