Acme 540 Prop

Ok guys! I ordered up a new Acme 540 prop for my 87 Ski Nautique and it arrived last week. It's really one fine looking prop.
However, I did notice a slight problem, and therefore I haven't installed it yet. My old prop was the Federal original, and it had been reworked a couple of times but it looked ok (even tho the reworked prop is slightly smaller diameter 12.25). When I slid the new prop onto my prop shaft (13") I was very concerned at how little clearance there was between the bottom of the lowest prop blade and the top of the protective trailer cradle. There is only about 1/4" clearance, and it just seems too close. My old prop was also a 13" prop, but it was reworked so the diameter was smaller, and maybe when it was new (the boat) it was situated on the trailer differently.
I guess there are 2 thing I could do:
1: put a thick shim between the trailer cradle and the rails to increase clearance, or
2: reposition the foward bumper cradle so that the boat sits a little more aft on the trailer increasing clearance. Right now the back of my hull is flush with the back of the trailer rails. Where does your boat sit on the trailer? What would you do? Have you had any Acme fit problems? TJ

882001, that's about right where I'm at, somewhere around 1/4 of an inch. It just appears pretty darn close. Although if you rotate the prop slightly there's tons of room. I might shim the cradle about 1/4" just to give a little extra room. I'm worried that if I did something such as going over some railroad tracks that the trailer might flex slightly and the prop could contact the cradle. Are you happy with the 540? TJ

i am about to buy the 542 prop what does the rotation mean is it right or left. i have an 83 nautique.