Either will do but PSP22 is more of an energy/fluid drink and whereas Go is a just fluid replacement drink.

The Go drink is designed to rehydrate, whilst the PSP22 is more for high energy riding. I use PSP22 for fast riding or racing and Go for long distance rides of lower intensity where dehydration and cramp can creep up on you.

I've been using PSP22 for the same situation and I've not had any problems.

If you are using this to rehydrate, then the electrolytes will aid absorption of water, particularly if made slightly weaker than normal (hypotonic). If you need a fuel strategy then try the PSP energy or just do what I do and pile into a big plate of porridge before a big ride. I can go 80 miles or more with just the addition of one gel and not feel hungry or tired.