The issue is fairly common to this boat. The shield as others have mentioned and tight line to guide the sheets above the catching corner of the tabernacle are a great solution. I have also found that the faster the tack... (a snappy tack) will often not have the sheets catch. To do a snappy tack you do not release the working jib sheet until the jib is almost backing, ie the boat is head to wind. You also tack very quickly... helm hard over, so that when the wind catches the new side of the jib it snaps over flailing the old sheet behind it. You have to be quick on the new working sheet to trim it asap.
I personally cut a popl bleach bottle to act as a shield. The 2 litre size worked well, cut the top and bottom off and slip the tube around the base of the mast the next time it is down. Gravity causes the tube to slide down and cover the tabernacle corners... looks ugly as sin though!
