My take on bidding for an upgrade.
We have done it 3 times and it was accepted twice. However, we bid on a category upgrade, Reserve Collection Mini Suite to a Full Suite. We also bid with the assumption that we would be happy with the upgrade regardless of location. Also, I would not expect the bid to be accepted with a low ball amount unless the cruise is not selling well.
If location is very important to you, bidding on an upgrade might not be your best option, especially assuming the OP is bidding on an upgrade within the balcony category. The cost may not be offset by the benefit.
Enjoy your cruise. 🙂