Using standard jig for square-edge worktop

I bought a standard jig that I was expecting to use on 38mm postformed w/t but have actually decided to buy 28mm square-edge instead.

I know I can remove the trim from both edges and butt them together but honestly I'd rather use my router to do the join except not using the full length of the short part of the hockey stick mitre.

I was wondering whether, instead of buying another jig, I could use my current one, attaching a straight piece of wood between the peg and the w/t so that the...

Using standard jig for square-edge worktop