Thanks for more comments since my previous reply!
FingersEddie, yes, now it's very hot in Bangkok, temperature can be 40 celcius all days from 8AM to 5PM. Luckily we've had rain almost daily. That helps a lot.
James, we don't have the scale cable, just built it out of the box. The supplied strings look OK to me.
Mikeym, why do you have to mix parts from Tamiya and Tri Star? What's the point?