Sorry that I did not see this posting sooner, if I had I would have recommended that you modify the charging base in a different way.
I had a look inside both my Cobra and Midland chargers and noticed that they were essentially the same electronically but the resister value in the Cobra has about twice the resistance of that of the Midland charger. This difference would reduce your charge current to approximately ½ as in the Cobra model that I never turn off and that the manufacture indicated is safe to remain on continuous charge.
See my post on this issue. CLICK>
I forgot the exact resister values (one for each bay) but if you like I could open both units up again and give them to you. This modification would have allowed you to remove and restore back like original without adding the hole and switch and also the resisters would have costed only about $1.
In your case now, if I were you, I would have both resisters values connected to the DPDT switch so as to have a rapid charger OR a trickle holding charger.
This type of modifying is beyond the scope of most users and would void any warranty. Midland has a 3 year now.