Assume you mean controlling the spundiong valve during fermentation to leave a carbonated beer. I'm sure you can do it that way, as long as you don't want to dry hop as you'll have to take the lid off to get the hops in (dry hopping via the bottle is a waste of time). Having said that I usually ferment under a bit of pressure, but to carb this way I think you need to try and close down the spunding valve near the end of fermentation - will be a bit of trial and error I reckonBased on your answer I might have misunderstood something. On question 2.
I thought that by setting the spunding valve at a fixed pressure the gas will only escape when the pressure goes over the fixed one and that way keep the fermentasaurus at that pressure. I had planned to control the carbonation that way. Am I wrong?
Thanks for the long and explained answer. :)