The primary reason your sheets hang up is technique, not the knot. Do not try to pull the clew of the sail around the shrouds.... let the wind do the work for you.... when you start the tack.. ease out a foot or two on the sheet.... bring the bow through the wind and let the headsail backwind, until the boom comes across.... then toss the old sheet completely off the winch and allow the wind to bring the rest of the sail across... stripping in the slack on the new sheet, but not trying to pull the clew across the deck..
An added benefit of this technique is a more effecient turn.
If you're working with a large genoa in light air.... you may still have problems with insufficient pressure on the backwinded sail..... in this case, it is quite common to station a crew at the mast to help the sail make its journey.
If you single hand alot..... and you are still struggling with the sail... there is a simple rig you can set up that pulls the center of the foot of the sail forward to allow the clew to clear the shrouds.... This is most often used on a cutter rig where the staysail allows a minimal window for the headsail to pass through.
I'm thinking RichH posted a diagram of the set up a year or so back.... but I can't remember the exact name of the device... you would need a cringle, about mid-foot, to secure a line which is run forward to a block, then aft to the cockpit.
Damn, Rich what in the heck is the name of that rig? I'm getting old and forgetful.