Ideally, you want the next size up, the Vent-A-Hood Professional Series BH240PSLDSS.

Ideally, you would want the hood 42" wide and 27" deep.

That gives you excellent capture area as well keeps the flammable wood away from direct heat.

Having the hood 31 1/4" above the rangetop is more than sufficient.

Thank you so much deeageaux. I'll check out the liner that you recommended. I had a feeling that the one we were quoted was too narrow. Your point about flammability is also appreciated as we were concerned about that issue.
I'm so glad that I asked this question.
Thanks again!