Chop Top 400 WHP 67 Mustang needs advice

[Imperial Beach Dad]

Hey friends! I was previously quite active here under the username "Geo Metropolis," and built a fully boat-tailed 3cyl 5spd metro but, loooong story short, I had brain surgery and lost a lot of things - like my memory ie passwords, and my job ie email access, but I never lost my stoke! So now I'm here under my online personality name "Imperial Beach Dad. looking to mod something waaaay out of the norm for this crowd. Well, all crowds really.

Thanks to kind people from the internet, I now daily a fully caged, 5.3 LS Swapped, side-piped, chop-topped, windowless 67 mustang - called the #Punishstang. It's my daily and my dadmobile and last year alone we did more than 12,000 road trip miles with kids in car-seats making friends and memories across the country. I'm about to head off on another 6,000 mile adventure and I was thinking back to my eco-modding days and had some ideas.

When I did my front valance for SEMA I included a partial belly pan under it and saw a small increase in MPG and it got me thinking. Bellypans are easy enough, and with my subframe connectors, it should be fairly easy to bolt on some sheetmetal I came across. Sorry to cheat on you coreplast lol. But what I'm really interested in is spoilers

If I remember right, part of what started this whole movement was an article in some magazine where they welded on a sort of duckbill spoiler that pressurized the air into a more slippery shape. If this is the case, can I possibly extend my current spoiler (I'm thinking Plexiglass with some spoiler support turnbuckles) to a shape that would have this effect?

Using some editing and the aero template I came up with something like this

Before I break out the self-tapping screws, I wanted to make sure I'm on the right track. I have other questions when it comes to a rear diffuser, trailing the bellypan, but that's for another day.