Since we have 98 octane here in Sweden I have set the timing at 38* total.
But is it possible to run 95 octane with 10.2 :1 CR?....if so, what should the timing be set at?
Are there any advantages or disadvantages to run a lower octane?
Are there any other things I should consider?
I think the issue is as follows. Yes you can run 10.2 with lower octane but there might be a price for that decision. Sure you can run lower octane but as pointed out above are you sure the rating systems are the same? I can't tell if the octane rating in the US is calculated the same way as it is in Sweden. Let me say this however. At some point you are going to have to back down on the timing to run lower octane gas. How far back on the timing? Can't say. As sure as death and taxes at high timing numbers, with low octane, the thing is going to ping. Pinging is destructive that is also a sure thing ....without a doubt.
I have gotten to where every little bit of perf. just doesn't matter to me anymore. I don't want to be searching for high octane gas in a mid to low octane gas world. I would rather be a little lower than I might otherwise want to be on compression and free to stop at any station to fill up.
In the end this really boils down to what you want. If you just must have that extra few HP then leave the compression but be ready to reach a day when you have to turn back the timing. You might not like turning back the timing any more than you like cutting the compression.
"You can't have it all" or at least "You can't have it all and count on things being the way they are now". Gas can only get more expensive, government is gonna keep screwing around with formulation of gas (look at the CRAP E-10 / E-15 we have in in the US). If you stay at a higher compression and higher timing settings you are gonna be caught in this squeeze sooner rather than later.
If I were you I would consider this equation of gas / compression and performance. This is just another go round of the issue with lead removal in the US back in the 1970's. The gov removed lead and all ya heard was weeping about "Compression, timing, power loss" Essentially people just had to get used to the fact that w/o lead ya can't run higher compression ratios and or higher timing on the street. Also at some point if you crank the timing back far enough you run into heating issues...low timing settings will add to cooling issues. I think you are contemplating essentially the same problem we faced here years ago. The only difference being that today the issue is octane rating not lead content.