Im afraid I dont have a Profec, but I do use the Blitz SBCi Boost Controller, which operates a similar system.

The answer to the above is yes, but you should consider going for the Dash -34, which I found to be more reactive, and generally better.

The gain in my experience on mine was better at about 15%. The higher settings are only useful for external wastegates. Find out what works best for you, but Mine is usually between 10 and 15. If you are finding it surging up and down a lot (frequently) you probably have the gain too high.

The set level should be set up with a boost gauge, but remember that it will vary depending on conditions (ambient ext air temp etc).

I use the target boost settings on the Blitz which means it boosts till it finds the right level, and then stops, though I must admit, the normal % set mode gives better response.

So basically, set the level to suit the desired boost level.

Hope this helps

JJ