I'd like to give my daughter a few more pennywhistles for a Christmas gift this year.
She now has a set of "Generation" brand whistles in the keys of;
G,F,Eb,D,C,& Bb.
As I'm not a whistle player,what additional keys would any experienced Pennywhistlers here suggest I purchase?
I'm looking to purchase another 4 or 5

Also,any suggestions on moderately priced brands of P.W.
I bought the set she has now ,here (U.S.), 6 or 7 years ago,for about 10 to 12 bucks a piece ,if memory serves correctly.
They seem to've held up pretty well.

Thanks,D.B.