For me a bunker is a wholly unnatural experience and I want to be in one for as little time as is possible, if at all...
Regardless of what the rule book might have to say on this (who actually reads it anyway, right...
) there is also the matter of time, how many practice swings do you want to take...???
Given you can't ground your club in the pot, I don't see that you can take a proper practice swing in a pot anyways...
All you can do is try to visualise it then play it and hope you get it right...
For me it's get in there, play your shot, and get out.