I would strongly suggest using modeling clay on the top of the piston then run it to TDC. Mic the clay to see how much room you have. Typically, .060 was what we used to take off. We took .100 off once and ended up having to gouge out the corners of the cylinder head to match the pistons.
We ran "blue" Sunoco 260, then it turned red but still gave you a headache if you spilled it on the concrete floor. Take AS MUCH as you can then pick up some octane additive from the suto parts store....