Thermoquad

Engine will consume a greater volume of E85 than non-E petrol, so you would definitely need to increase n/s size. I would go to 0.120" with your intended combo. You can drill the existing seats to the new size. Use a new drill to minimise the burr that is raised. You will need to smooth down the new seat. That requires a perfectly cylindrical tapered punch; or a small ball bearing also works. Tap lightly & check for leakage afterwards.