Applying new proseal over old proseal

Working on a set of RV10 fuel tanks here. I?ve installed the stiffeners but failed to tape off in between the stiffeners where the ribs go so there is some excess proseal where the rib would sit. It?s not covering the holes or anything and doesn?t run all the way from one stiffener to the other but the rib will not sit flush to the skin due to the proseal. Do I need to remove the old stuff somehow or can a just put down a new layer on top after scuffing/wiping with MEK and continue?
If I do need to remove it, what is the best way without hurting the seal/bond I already have around the stiffeners?

Thanks

Proseal remover

This might help.
http://www.vansairforce.com/community/showpost.php?p=946140&postcount=1