@riley804
Yes riley, you can go to each shipper’s site and get an estimate of what it will cost to ship with them, but I was answering this question from the OP:
I’m wondering if there’s a “best” technique for figuring out shipping charges. I know there are general guidelines on the carriers’ websites, but are there other ways to determine fairly precise charges?
and to the best of my knowledge there is no site that will give you an estimate for more than one shipper. I assumed that the OP knows that you can get an estimate from each individual shipper.
The first part of my reply:
You can negotiate with the buyer that he or she pay actual shipping costs
was in reply to this statement from the OP:
I don’t want to gouge anyone, but I don’t want to lose $$ in the process, either.
Sorry if I wasn't clear.