Track location
Directly under where your old tracks are(were) the non skid is smooth-there is a smooth line that runs alongside the cabin top on a gentle curve, and ideally, you want to put the new track directly where the old one went. The only thing to be careful of is that since the new cars are wider than the old cars, you should check and make sure the cars can slide unimpeded without bumping into the cabin top sides-if they do, move the track JUST far enough outboard so the cars can slide freely. No more than this, as the farther outboard you go, the wider the sheeting agnle becomes and pointing will begin to suffer
Now, you will improve things slightly if you can have a slightly longer track at both ends-pushing the forward end another inch or 2 will make a true #3 genoa sheet and fit the rig better, and going an another inch or 3 aft will allow more adjustment in the upper ranges of the large genoa. If you do not have anything bigger than a 150, or smaller than a 110, and do not plan to, then none of this (longer length) will really have any impact. The standard track is about right for a 152-153. A low cut 155 will barely fit, but you have little to no adjutmsnrt available to drop the car aft as the breeze builds, so to have a bit more track aft will give you more trim range. If you have to make a choice between farther aft or forward, go aft. The length and location of the std track is plenty for 150, and as I said marginal for a 152-153, and having a bit more aft track lets you flatten the big genny a bit more. Sorry to repeat.
One other thing: If you cannot get the track bent along the curve and must lay it straight, keep it as close to the cabin as you can (while allowing room for the cars to slide). Of course, cosmetically you will have to deal with the smooth part of the deck where the old track was, but this can be dealt with.
BTW-it is snowing in Tucson (or it was last night when I got here for a trade show!).
Same backing hardware should be OK.
Now, wait to hear from some of the guys who have done the Garhauer swap and see what they say-especially about the backing hardware.
This is a great thing to do-because even if your biggest and smallest sails are not at the "limits" in size (for the std. track length), the ability to really set the leads correctly for any size genoa in between (your 110-135% genoas for example) will make a HUGE performance improvement....
Sailing along with your 130-135 upwind, and starting to get overpowered, drop the car back 6-8 inches and watch the boat "get happy".. Or beam reaching, and seeing the top half of the genny luffing with the car in the normal upwind spot (and thus not having the top of the sail working for you), you can pull the car forward until the top half stops luffing (and the top and bottom telltales now break at the same time)...
Enjoy!
S