Cold start on LPG, vaporizer freezing issues

I read a lot about LPG vaporizer freezing over on cold starts and the need to start on petrol until the engine has warmed up a bit. I’ve read that some electronic LPG systems on newer cars will only allow 20 starts on LPG before the system is locked until a technician resets it.

However, when I start my 30 year old car on LPG, the vaporizer gets only slightly colder than the surrounding air. That car has 1.6 L engine with carburetor. Lovato LPG system has the cold start (red) button, which enables really easy starts, it only takes one or two turns for a completely cold engine.

On the other side, that car works horribly bad on petrol (I know I have to wait for it to burn the previous fuel when switching to another one, the main switch has neutral position). The mixture is way too rich, the car doesn’t start well and stall easily. On LPG it works perfectly.

So, my question is, how bad is it to start on LPG considering that the my vaporizer gets only slightly colder and that I drive very carefully for the first few minutes? The previous owner of this car never used petrol, so I guess cold starts on LPG can’t be that bad in terms of shortening the life of LPG components.
My other question is – would I be able to start the car in cold weather (-10C, 14F)? I know that Butane has boiling point of about 0C, so it would be Propane only for a few minutes.

Thanks in advance.