tall rear valence(s) questions, Need some clarification... Options

[Speedo]

Allow me to ramble...I have a 914-6 and one of Ben's GT3 mufflers, so either way I have some work to do to accommodate the twin barrels pointing out the back. If I had a real 6 tall valence, I would need to weld the tailpipe outlet shut and create one oblong or two symmetrical openings for the outlets. Good and bad news is that I don't have a tall 6 rear valence, so I don't need to stress about destroying a real valence to create what I need. But I do want a valence. Ferg kindly set me up with a short 4 valence and I have massaged it back to it's original shape, thinking that I might flatten the lower lip, add steel to make it a tall valence...and then decide what to do about the tailpipe exit. Before I start adding steel, I wanted to ask the wizards here what, if any, was the difference in the angle the short and tall valences tuck under the rear of the car. Is the angle/arc the same for the short and tall valences? Something tells me the arc of the short valence is more abrupt than the tall, but as I don't have a tall to measure or compare...I'm relying on you guys. Thanks for your help in advance.