I would not use E10 in a classic. The ethanol plays havoc on all the fuel hoses, diaphrams etc. It also promotes rust in the fuel system.
We are incredibly lucky that we can still buy proper petrol in 95 and 98, in some places you cannot and you can read about all the problems it causes for classics. This is the case in many parts of the USA and in the UK.
This is not the case for modern cars as they are designed for it.