Many boats (especialy those equiped with double-track luffs) will have two headsail halyards up the front of the mast. even if one of them is busy holding the top of your furled headsail, you still have a "spare"
If that is not an option, then there is always the spinnaker halyard. This is mounted to the very highest bit of the masthead, so as long as you are not running ridiculously undersized rope as your halyard, then it will be more then adequate.
If you plan to sail single handed, off-shore...then you may well want either the "spare" halyard or a decent capacity spinnaker halyard before you leave the dock...just in case.
It is not going to be to relevent to you in single-handing, but our spinnaker halyard is also our desegnated crew-overboard retrieval system if it should prove neccassary (this is on acount of havign a nice pivoting block for it at the masthead, instead of just the inset sheaves as on the headsail halyards).
As to your issues with bosun''s chairs. The self-climb systems tend to be varients of climber''s assent harnesses available form rock-climbing shops (only at a big markup to be called yachting gear) or are ladders made of nylon webbing sewn into looped foot-holes. This is then hoisted up the mast while secured firmly to the deck and a person can climb on up.
Even with powered winches, I would never rig a remote control and hoist myself up the mast if I was the only one on the boat, the potential for being the piniata on board the modern day Marie Celeste is just too great. I think being stuck up there would only be funny for the first 20 hours or so.