b-flat contrabass straight-need higer chair?

I think it's common to use a medium-tall stool.

Are you getting a Vito or Leblanc one? Either way, they're both pretty much the same height (or should that be length?).

I seem to remember Leblanc recommended the use of a bar stool or a high stool that (string) bass players use to play their straight BBb contras while seated for both the plastic Vito and metal Leblanc.

I found an old stool with adjustable height by turning the seat. It was very handy. Where I would normally tighten the neck strap, I lowered the stool. Easily done while performing by rotating the seat during a rest. Very slick for the contrabass, just more stuff to carry along.

Think old pedal organ stool.

Or you can play standing and put it on a sturdy box or something to raise it up.
I may sell mine if your still looking.
--bob

You need a bass stool to play them sitting down. My high school had an old Leblanc "paperclip" contra that, to me anyway, felt better, sounded better and was more practical (it's hard to physically fit one of the straight plastic ones anywhere in a wind ensemble). Plus, they look like industrial clarinet machines.