Newbie Intro. and a few questions

Short introduction: I'm an amateur photographer in the Washington DC area
shooting mostly medium format on-location portraits and architectural stuff.
I shoot mostly B&W print, but also use transparencies (usually Fuji Provia
100). I am fascinated by the potential of pinhole photography and am looking
to buy a pre-made camera after seeing the beautiful examples on the resource
page. I use mostly all-manual cameras, so getting into pinhole feels pretty
natural. I hate the way modern electronics can get in the way of the image
making process.

Are there any practical reasons to shoot at 4x5 rather than 8x10? I suppose
it would be easy enough to do both, but I'm wondering about people's
preferences for architectural and portrait work. The multi-format Zero2000
looks like a good starter as well given the choice of formats for standard
roll film.

I must say I am blown away by the quality and creativeness of the images I
have seen on the April 28 pinhole day gallery -- really inspiring! One of
the best photographic events I've ever seen -- simple and powerful.

Anyway, I'm here to learn and am glad to participate.

R.J.