You got it dead right there . Nitro is just an additive in glow fuel and isn't a necessary part of the fuel. The only thing that's necessary is the methanol because it's the only thing that keeps the glow plug glowing after the battery is disconnected. The next thing in fuel that's necessary is the oil which lets the engine keep on running . Once you've got both those things then anything else is just an accessory.

If there was no such thing as nitro then every engine would be made with a compression that suited just methanol (around 13:1). But nitro is cheap in America so they all use it (although lately I've seen a swing away from it) and because America is the largest market for engines then most companies have modified the engines to make them suitable to use nitro. This means they've had their compressions lowered to suit (down around 9 or 10:1). All engines will still run without nitro but not quite as well as they could do. Our loss . The difference though is fairly small so nothing to worry about.

The fuel you use is true FAI fuel (which is exactly what I use too) but any fuel without nitro is known generically as FAI fuel no matter how much oil or even if it's synthetic oil. Nitro doesn't really affect the life of an engine because they're not running all that much faster than an engine on zero nitro, they'll just use a heck of a lot more fuel over their lifetime than one without nitro .