If you take the RON+MON of ethanol to be 113, adding 10% ethanol to 85 octane gas would result in 87.8 octane for the E10 blend. So removing all the ethanol from 87 octane E10 would result in ~84 octane E0.
However I find number for the RON from 120 to 135 and MON of 100-106. I don't know why there is a range. The higher the octane the ethanol in the E10 is, the lower the octane of the resulting E0 after the ethanol is removed.
How are you removing the ethanol? It seems like it would be difficult to remove all of it.
Where I am E0 is difficult to find and costs a lot more, so I have been using E10. I have not had any fuel system problems in any of my outdoor equipment. The generator and lawn tractor are 25 years old and still on their original fuel system parts. I've had to rebuild exactly one carburetor and that was due to letting a saw sit for a few years with gas in it.
However it does not get all that cold here, rarely into the 20s. To get phase separation, which is the main problem ethanol causes, you need water in the fuel and low temps. If low temps are unavoidable, then you need to keep water out of the fuel. I think that would be easier than removing the ethanol.
The first thing to remember, is never leave any fuel in the tank, and run the equipment dry before you store it.
I am on Vancouver Island, and for now, marked gas has no alcohol and is 91 octane.
When I have been stuck using E85, if the fuel is going to sit for any amount of time, I add a fuel stabilizer, . I always filter my fuel through a 100 mesh filter, or a chamois, and if there is any water, I can see it immediately. The chamois, will remove the water.
I have filtered out the alcohol, by adding water to the 5 gal container of gas, then shaking it to dissolve the alcohol. I then pour the gas into a gallon jug, and let the water and dissolved alcohol settle to the bottom.
Then, without disturbing the water at the bottom of the jar, I pour off the gas on top. The remaining gas can be removed by siphoning the water out from under the gas.