Commercial Bidding


I have been in the roofing field for 15 years in northern Vermont. I have done very limited commercial roofing due to demographics. I have recently been asked by a big company if i would like to bid on there commercial projects. I already have all my insurance in check. My question is what are reasonable commercial prices to charge per square for:

-standing seam

I dont want to seem too low and i also dont want to be too high. Just looking for some kind of base numbers to work from.