"Mark Shaw" > wrote in message
> I've historically just figured on about three hours, but
> this is the biggest roast I've ever dealt with, and I need something
> more like a time-per-pound figure.

If three hours worked, figur about 20 to 30 minutes more.


..
>
> Oh, also: this is the first Xmas I've had a convection oven at my
> disposal. Convection, or normal? Or does it matter?

Convection will cook faster so use care if you try it. Rule of thumb is 25%
less time and 25 degrees cooler, but you are on the cool side already.