Initial Temperature for Simulated Annealing

Hello

I'm trying to use simulannealbnd for parameter optimization. My big problem is the initial temperature T0. The default value is 100 but this seems not that good.

I have eight parameters with the following ranges:

[-5,15]
[-15,3]
[0,1]
[1,30]
[0,4] (four parameters)

My cost function can take values between 0.5 and 1. I want to use different AnnealingFcn (@annealingfast and @annealingboltz) and different TemperatureFcn (@temperatureexp, @temperaturefast and @temperatureboltz). I'm using the following combinations:

@annealingfast + @temperatureexp
@annealingfast + @temperaturefast
@annealingboltz + @temperatureboltz

What are reasonable values to try for the initial temperature?