lookups choosing tables

here is what I need to do...
I can do a basic two way look up but I have 30 tables all with different products.
If I create a drop down list with all the tables listed how do I link the drop down to the table look up formula?
All my table have a width row and a height column.
I need users to select the drop down product then enter the width and the height needed to supply the result cell.
Thanks in advance