How can I combine two beats in style A into one beat, make the tempo 70, so that it will sound perfectly in the new style?
I just test it on built-in StyleCreator (no external software)
In the first page of "StyleCreator" you have a "Tempo" value.
When you start assembling a new style, StyleCreator gets the tempo from the original style.
So if you start with the style from where you want to take the "intro" part part (tempo 140) the "default tempo" of the new style will be 140.
On the other hand if you start with the Main variation, from the second style (tempo 70), and then add the Intro form the tempo 140 style, the StyleCreator will take the default tempo of the second style (70).
So you get what you want.
In any case there is a "tempo" value on the first editing page of StyleCreator.
So the only you have to do is just change the value from 140 to 70!
You don't have to restart the assembling processes. Just change the tempo.
Al this is possible on the built-in StyleCreator. NO need for external software.