Iam,
I think your problems and solutions are as follows:
Hand slipping while stretching:
Make sure you are gripping the inner structures and not right behind the glans. Try a gripping aid, like rubber gloves or baby powder, these will reduce the amount your hand slips. To be honest though, it took me ages to work out how to manual stretch and I still don’t find it particularly easy. That’s why I hang.
10 minute stretching and slapping:
Stretch for whatever is comfortable. I think you must have got the slapping from another site, I have seen it elsewhere, but it doesn’t seem to be advocated here. You don’t have to do a set amount of slapping, personally I don’t think that it is very effective, try 10 slow jelqs instead. All you need to do is refresh the blood in your penis.
Too much skin!:
I too am uncut. Really finding a comfortable way to stretch is very personal. My advice is to sit in bed one sunday morning and try out as many different ways as you can and see which works for you. I vary my grip whenever I am manual stretching and none seems to be any better or worse than the rest.
As for sack skin while jelqing, you have to get used to it. Some people will pull the skin back after each stroke, I’ve tried this, but it just adds too much hassle. I just get on with it and deal with a bit of extra skin being pulled up. Just make sure that it is well lubed and treat it like normal skin.
Hope this helps.
LB