Keep the SP101. It's the best all around gun there is.
And besides, with Python prices being what they are, you'd be losing a good chunk of change not to sell it. Of course it will be worth more later, but assuming that you are selling for money reasons, you need the money now, not later. And as someone said before, would you take the Python hunting and not mind if it got dinged up or fell in the drink? I didn't think so.
It's the nicest gun. But not the most practical.
The SP101 is small, but has enough barrel length to be practical in all your requirements. it is also a tough bugger. I'd stick with the SP101.
Edit to add: depending on your body type and where you live, the SP101 would be a hell of a lot easier to conceal in the summer time that a GP100 or Python. I'm not saying that those can't be done, but I know I couldn't pass it off with anything less than a heavy flannel shirt and vest over that.