Hey Henry,,,,,
I own both rifles in .22 and can tell you from personal experience that either one will easily do the job on squirrels or any other small game. I love both of my rifles and both have done an excellent job for me as hunters. I've said more than a few times that my .22 Panther quickly became my favorite small game springer,, and that statement still holds true, but my B26 .22 is also a sweet shootin rifle. My Panther does put out more power than the my B26, she's shooting in the mid 700's, but my B26 is still puttin out more than enough power for effective small game hunting.
The Panther is longer and heavier but it has a very nice trigger and a really nice synthetic stock, in my opinion one of the nicest synthetic stocks I've run across.
The B26 is lighter and perhaps easier to navigate with in the woods and it also has a really nice trigger,, remember,,, the B26 is a clone of the R-9 and it's trigger. The thing that might swing my vote if I could only buy one is the fact that with the B26 you're gettin a rifle that is professionally tuned by a man who really knows his stuff,,, and you're gettin it for less than the cost of the untuned Panther. One other thing,,,,,, in my opinion the B26 would be much more comfortable for your sons to shoot as opposed to the long and heavier Panther....
I guess maybe I'm not helping you much as I really love both of my rifles and consider both excellent small game guns,,,, I just wanted to point out the positive attributes of both rifles.
BTW..... if you decide on the Panther you can get it for a much better price from Straightshooters.com or a couple of other online dealers.
I'm sure others will chime in with their advice. Let us know what rifle you choose.
One last thing,,,,, personally I wouldn't go with the .22 Whisper,,, not if I could get either a Panther or one of Mikes B26's.... You KNOW the whisper is gonna need tune work, the trigger is lousy, and it's just basically the same power plant that's in the .177 Whisper.
Ok,, I"m done now..........................................
Jeff