Michael
The S1 is trickier in some ways, easier in others.
for instance, S1 landings are shorter than S-2A and especially S-2B landings because of the extra inertia of the S-2.
e.g. at Leicester and White waltham - you can often get a S1 stoppped before the intersection.
what I meant was - you have to get experience in a fast taildragger rather than a docile one, and no-one is going to let you loose in their own S1 as Stik says. So building experience in various conditions in an S2 is a good idea.
You could do the bare minimum in an S2 an jumo into your shiny new S1 - but inevitably the next 10hours or so are going to be dangerous. There have been a number of accidents to show the truth of that.
also - you may not be able to get insurance for your new S1 these days until you've built some 2 seater hours