I've seen the Speedy Metals site- aside from online ordering it has a TON of information about the metals they sell. Apologies in advance if you've already done this homework: do you have a steel retailer in your area? There's a place around here that will cut to order. I built a swingset for the kids and needed some triangle shaped plate to use as gussets for one of the overhead members. They took measurements (and my credit card number of course) over the phone and it was ready quickly, and they're a good source of odds and ends ("drops" from other cuts) that they'll give away for free or cheap. You might save the UPS charges, at least.
And I count 7 weekends 'til the end of the contest, plenty of time! Good luck with the stove.