Query size and position of target cell in table?

It really sounds to me like you should be using a control panel with a Listbox control in it. A Listbox control has events that cover all the stuff you've been trying to coerce a table window into doing. The only hitch is that the Listbox needs a text wave representation of your numeric wave instead of the numeric wave itself. That means a bit of code to make your user's edits update the numeric wave.

Thanks - I'll look into that.

Have you considered using setvariable and popup controls within a panel? SetVariable controls have options for limits, increments, and so on that are easy to implement, and can be used to set the value of a wave element. Popups, checkboxes, sliders, and buttons can have action procedures that set a wave element based on the selection. You can build a panel using dialogs (show tools and add controls from the panel menu) and generate a recreation macro to create some code as a starting point for coding the interface.