A bit confused here.

The balance tab on the leading edge of the elev is 1/2" wide. Instructions (Step #9) say to cut root cap strips for the balance tab from leftover 3/32" balsa. The only 3/32" I have is either 1/4" or 3/8" wide, none is 1/2" wide. Does this mean that in order to make this cap, I have to glue two of the 1/4" strips together to make one 1/2" wide? Or is it supposed to just be 3/8" wide, thereby NOT being as wide as the balance tab is OR is it 3/4" wide so there is a "rib" at that point too?

The same thing applies for the root end doubler caps (Step #10). the root end of the elev is (1/4+1/4+3/32-a rib thickness) or 19/32" wide. Again do I butt glue 2 pieces together to make up the whole width or is the cap flush with the root or what?

Just find some balsa from the left over diecut sheets the same thickness and cut a piece the size you need.[&:]

I wasn't clear. Is the cap the width of the balance tab (ie 1/2" ) and the root?

Yes it is. You got it right. after that you'll sand it to match. They should say make balsa look like picture.
[&:]

Thanks.