Speed is determined primarily by your settings file.
There is a program that automatically generates a settings file based on your maxwide settings.
Default is 5000, if you lose your turns lower it, otherwise leave it as high as possible.

You can speed it up quite a bit by setting the priority of the silver.exe process to realtime.
Open the task manager and right click on silver.exe and set priority.

If you pc is slow this might make it overall more unstable, it's what happened with me.
With slow pcs it's much better to significantly lower max wide setting.
I lowered it to 2500 and still got to rank 13 with midrange shaman

I don't think there will be significant changes at winrates if you raise it even higher.

There is a certain point after which it doesn't get that much better really. If you increase it further you may get just a few extra wins out of many hundrends.

If you use the bot very prolifically, like 24 straight hours usage for several days, you might get a little bit extra out of it.

Try it out and maybe post results as well as your specs for people to have as a reference point

Please read the notes in the default settings.txt to learn a bit about what each does. The main 2 settings are for limiting the number of calculations in extreme circumstances when the board is full and there's like 10 moves it needs to do, but have no affect at all on the majority of boards because simple boards have few possible combinations of moves.