I am going to pour 2 ~8.5ft x 3.5ft slabs next to my house, right up to
the foundation. I a then going to install a couple of 3x8 sheds on them
(Arrow vinyl/steel). Anyway, my initial plan was this:

Pour the slabs at a slope, (1/4" per foot) leading away from the
foundation, to ensure water is led away. I was going to accomplish this
by having the boards on the sides of my pour sloped at the angle I want,
and then using these boards to "level" the concrete out when it is
poured, this giving the concrete its slope.

First, will this work? Will the concrete stay at this angle?

Second, is there another way to prevent water from flowing towards the
foundation, besides this? I will have to shim the sheds up, and that
will be a hassle, and I will have ~3/4" ridge at the entrance, which is
somewhat undesirable. Could I pour the concrete true level, and then put
something at the junction of the existing foudnation and the new slab
instead?

thx