I found out about Copes today for the first time also. Funnily enough someone posted a link on www.taurusarmed.net regarding them too. They have inexpensive P95 and Taurus PT92 magazines -- and I can use both.
I am not a huge fan of aftermarket mags for flush fit. I know, a slam pad can be made and attached, but, I prefer Ruger factory mags for 100% reliability. (I have had bad experiences with other mfgs in the past)
I might look at the high caps for 20 and 30 rounders.