I looked through my shims today to give my 1000 a bit more lift (it was super light) with my 255-2/115+ and didn't see a +0.5. Looked at an online shop and the standard six shim kit doesn't seem to have one either. Does one exist? I see that there is a -0.5.

The 1.0 was like riding an elevator even in 10 kts - I don't need that much. Came in and swapped back to the 0.

I have an old 255 which I can use with a -1.5 I guess?

I think the + 0.5 shim was a later addition to the shim set, to use with the newer -2 deg 255 tail wing for the iqfoil.
My older 2 x 95 + fuselages don't have this shim.
When they were introduced, apparently you could ask your local Starboard dealer for one free of change

Thanks, all. Have emailed my dealer.