I don't use them , what he said... The general idea is to keep your CCW primary as small and as concealable as possible and when the SHTF then you can take out the banana clips...Just remember if you are going to CCW the gun, the extensions put length on the butt which makes it harder to conceal.
I did the same thing...worked well for me..It's all about preference...you may have to try some different options.
I have a couple of the Pearce extensions. I only use them when loading up for the range. I use the standard factory magazines and base plates for CCW. As was stated by Alex, the idea of keeping your firearm concealed, the smaller the better!