Good size of blank and preferred woods

Hi,
I'm going to be making an appointment at Bell Forest products in Ishpeming pretty quick to get some exotic wood blanks. They are letting people in by appointment only, but at least i can go see the pieces for myself.
I was wondering what size blanks would be a decent size. They have some bowl turning blanks 4x4x2 on up. The also have a box of exotic wood pieces, fifteen pounds for $35, so I was planning on getting one of those and trying to learn now to laminate small pieces together.

So what is a good size of blank to start with for a standard sized slingshot?

Many of the templates don't have measurements, you just resize as you'd like and print out the page. I'm using an iPad mini and don't currently have a printer, so I'm eyeballing them.

I'm guessing most are 5" tall or less?

What is a decent thickness that would give me room to make a thicker palm swell if I want to?

I didn't find one, but I was wondering if there was a thread or chart that mentions wood that is superior to use for slingshots, or a Janka hardness or density number i should be looking for?

Thanks, Lisa