I have just assembled my block with forged ross pistons and eagle rods.
I have measured the volume of the head and the volume above the piston at TDC with a sheet of perspex and syringing oil in.
So I have made a quick compression ratio calculator to help determine the head gasket I should get. It uses volume at BDC/ Volume at TDC. I have attached a pic of the excel sheet if you'd like to see.
 
So my question is basically, what Compression Ratio should I be aiming for? 
Block is 1mm oversize, gen3 head, ported, 1mm oversize valves, GT3076R with 0.82 A/R, Haltec ECU and W2A intercooler. 
Thanks
 

What fuel are you planning to run?

For higher boost strategy on pump fuel - 8.5:1
For better response & E85 I'd go with 9:1

1mm OS in a 3s block? Id go 9:1 and keep boost lower.

With that turbo on pump, I'd rather 8.5 & more boost so the tarby's in its efficiency range. One thing myself & Hitman noticed with my motors over the years is they respond better to more timing, boost & lower comp when on pump 98.

BP ultimate will be what's used, E85 isn't around where I am. Yes 3S block
A 1.676mm will get me 8.63:1
A 1.778mm will get me 8.57:1
A 1.905mm will get me 8.48:1
This are all based off my volume measurements being exact, which they wont be but should be close enough.
Thanks again

Either of the first 2. Too small a difference between em.

As above.  Obviously something to note is that compression ratio given on pistons is with standard headgasket thickness (~1.4mm?).  You've done it the right way and measured everything up, but for others your compression ratio may actually be higher then what your pistons are designated at if you are running a 1 or 1.1mm gasket.  I had planned on running E85 and was going to run around 9.5:1 CR.  BTW, I have found a few things off my car that you may want or need.  I have the front plastic trim from above the radiator, I have some wheel arch plastic liner here as well, not sure if it was from my car or another wreck I have had?  Umm, what else was there, I think one of the plastic cups from in the door trims.  I've been throwing everything I think may have come off to the car to one side.  Let me know what you want me to do with it.

Agree also. Mines even lower than that, but i don't think you should go as low these days with the slightly better fuel quality we now have in Australia.
 
 

Dylmrt is going to set me up with a Cometic for a good price.
My other option for the thickness I need is Apexi, at about double the price.
Is Apexi HG worth the extra $? 
 
Totenkopf, if you have room just leave them to the side if you can and we can work some way of getting them if I need them. I never let you know, the car came off the truck fine, a little scrape when going down as i was sitting in it. I haven't done any work on the car yet, just been building this engine for it while studying for exams. 

Dywer, I'm guessing that you bought James mr2?  If you did, good work mate - good to see its gone to another mr2 enthusiast.. I was thinking about it but just didnt have the time or money at the time.