[LS1Hawk]

It sounds like your boxes are already packed. You could take them down to a UPS store to get the exact weight and measurements. Honestly, I have a doctor's scale for weighting myself and I use that and it's been pretty accurate.

Once you have the weights and dimensions, when you create your listing select UPS Ground (I assuming that is how you are shipping). For the shipping rates there will be an option that says "let eBay calculate," or something to that extent. When you create your auction it will indicate that you are shipping UPS Ground and there will be a field for the bidder to enter their zipcode to get an estimated shipping rate. It's usually pretty accurate but always be prepared that you may have to pay a little extra out of pocket for shipping. You can also offer more than one shipping option.

If this is an expensive item, I would also recommend insuring the shipment and getting deliver confirmation, which you will have to indicate during the auction if the buyer pays or if you will eat the cost.