Mike,

Straps: At your size you may just not need the set on the far back... I am 190 and sail with my wife so I would need it well before you. If you do want it, they will not get in the way of the rudder. If you are trapping, you would never turn the rudder that far on an I20 anyway. I would not worry about them pulling out, you can carry the boat by them. At your foot size, you may have a problem with the standard Murrays set. They are adjustable but with booties mine are tight on my size 11's. You may want to put some kind of spacers under them to get some more room.

Rotator, downhull: I have not see the rotator run to the stern. I guess I would not recommend it. In a real blow, your crew should be playing your rotator and downhull... i.e. when you are at max downhull you can under-rotate the mast to stall the leading edge of your main... and stay in control in another 5-10 mph of wind speed. Better to just make sure they are accessible to the crew on the wire.