I'm thinking; encapsulating the entire spry in a single form, and have a single update button on the last tab 
yes, this is the way to go.
after the wizared creates your update page, it will be easiest to delete the existing form, create a new one, then edit the update record behavior and bind each database column to the new form fields.
Make a copy of the update page first that can be used for reference if you are stuck on something.
Delete the existing form on the update page. to add a new one, go to Insert -> Form -> Form to add the form to the page.
Place your cursor inside the form, then insert the spry tabbed panel
configure the spry tabbed panel with the tabs you would like to have, then start adding form elements to the tabs by going to Insert -> Form -> Text Field
for each form element go to the properties inspector, click the lightning bolt next to init value and select the corresponding column from the WADA recordset .
After the form is created, you will need to edit the Update Record server behavior. for each database column, click the lightning bolt and select the corresponding form element.
