Wallstreets in my experience are the least problematic of all my powerbooks without a functional backup battery, so long as they have a main battery. I'd advise you to put some money into a main battery and see how you get on first.

If you were to go the extra mile, the backup battery could be made from coin cells fairly easily, and much more cheaply than one could be bought ready-made. Buy some extra ones, and you have the basis for a backup battery in any powerbook.

The wiring and configuration will also almost certainly be in your machine in the form of the dead one.