Think it is a good idea as long as you use SH3Commander to do the swap. I don't like the teleport either and think that you should be able to do the transit when you move out of German bases to France or Norway along with your flotilla. Adding time on doesn't sound all that attractive either as this shortens your active time for patrols.
I think historically when a flotilla base was changed, boats at sea would have been radioed to end their patrols in the new base and those in the old base would have been sent on their new patrol with orders to end at the new base. There might have been a very few cases where subs may have been moved over land as they were to get them into the Black Sea at one point, but I don't think this was common.
Good solution Rosencrantz!
