I've been running my Tamiya XBG on Qwikfire 16. However, I propose to run it now on double yellow fuel (10% nitro, 20% castor, 70% methanol) - would this fuel be suitable? I know the nitro content is low but I'm not in need of max performance as I'm not racing the car and I'm getting Duraglow 25 for high performance.
Secondly, can I add a tiny bit of red food colouring to my supply of double yellow, just enough to colour it a bit so I can see the fuel level more clearly? I'm talking about a pinch of colouring in a litre, somthing like that, a tiny amount.
Thanks

A few drops of food coloring will not hurt anything. As for the double yellow fuel you're looking at, while you may have a small reduction in performance, the high caster content will be good for engine longevity.

Red exhaust.
Question: Can chilled fuel (from a refrigerator) add any power to the engine? Just a thought

Well, I wouldn't think so other than perhaps cooling the engine a bit. The idea of cooling air intake is the cool air is much denser and hence the amount of oxygen sucked in per stroke is greater, hence more performance. The density of the fuel will barely change with temperature.
BTW, the double yellow-stained-red fuel worked well, quite good performance and seemingly more economical (got more mins from the tank than with the Qwikfire 16 fuel).