If your model is taller than you, the prism won't make a significant difference compared to through magnifier viewing.
I often find myself standing on something
to raise myself up when shooting. Once,
I balanced myself on my mother's walker
to get the right angle for the photograph ...
... which as you can see got a good laugh
out of her.
But I digress.
I really dislike the prism finders. BUT I do
like another alternative -- a German company
named Baier makes an adaptor that allows
you to mount Hasselblad finders onto Rolleiflex
TLRs. It gets pricey, but you it allows you to
mount a Hasselblad chimney finder, which I
like a lot because it has a focusing magnifier
built in, so, if you're into reading glasses, it
gives you a way of correcting for that. And it
does a great job of blocking ambient light, for
a really bright clear view of the finder screen.
Here's a photo my wife Melanie took of me
photographing our son with the rig:
PS: You don't have to use the Baier adaptor.
With a bit of ingenuity, you can cannibalize an
extra Rolleiflex finder base (that's what I did).