Now I have undertstand what you mean..
question: why you need to turn OFF the Vsthost engine??
When you turn OFF the engine, automatically the audio/midi connection will be lost from Jack, if you run again, then you have to reconect all manually.
The OS script work only on this way:
1) you press the Vst/host MS key ( or one of the 8 asio patch, B4)
2) the OS run the filehost.exe Path and will make automatically: open with .wine
3) the .exe host start up under wine.
4) when the OS see available under the Jack connection the audio/midi port, the script will automatically connect the ASIO.exe audio jack on the FX Sever audio IN and also connecting the midi port to the keyboard.
IF you then turn OFF the host engine, you lose all and you have to reconect all manually.
Is better that you QUIT the host and then you press again the same MS ASIO patch, will run up automatically the host again.
Same way for the B4II standalone version or for the all standalone application.
The OS do NOT know IF you have turn OFF the engine or not, when the first time is up, the automatic scipt will not recalled again.
IF where NOT programmed on this way, every time that you switch engine, will open again a new Host and then you will have 10-100 same ASIO host running.
Anyway, I made a new test too and I will release on the new OS 4.2.
Download the new VstHost 1.47 double precision 32/64bit and replace the OLD vsthost.exe file with this new one.
NOTE: MUST have the SAME name file or the script will not run up!
Seem now really FAST, but better that you test too.