I don't know if I'm the only one that gets annoyed by their housing moving relative to the tray handles because of the long holes in the tray base. It has annoyed me for some time and I did something about it last night by making some aluminium spacers. I had put it off for over a year but it turned out to be really easy and took me less than an hour.
I had bought these things called 'red caps' some time ago, that are like little (ahem) condoms for caulk tubes....use half the tube, 'unroll' these over the opening, and the caulk usually doesn't dry out so you can use the rest later on. Anyway, when rolled up they look like little red rubber donuts. Poke a hole in the middle for the screw to go thru and used them instead of the spacers (or in addition to) and they added enough friction since they're rubbery that the tray/housing interface didn't slide. I'd think just a piece of inner tube along the top of the tray would accomplish the same thing, instead of having to crank down the screws really tight and/or shim the holes....you just need more friction surface area in the gap.
But nice fix - elegant, certainly.
I just screw mine really tight...
I have tried this. It doesn't work for me. As soon as I press the buttons to change the focus point, I push the housing forward. I also worry about damaging the bolts or worse, the anchor holes on the housing.
Anyway, for 45-60 minutes work, I'm happy.
I like what you did, I will try that. Now seriously I think this space is leaved by Ikelite in order to accommodate the tray in a way your hand get closer or at least confortable with the shutter lever. (Maybe you need it all the way back if you have giant hands...)