I have not seen that jet kit. Looks promising.
The Dyno-Jet kit has a few more pieces in it. If I recall correctly, there are two new springs, new needles, jets, a couple of drill bits, etc. It's a bit more extensive.
I don't really see a way to use the OEM filter without using the OEM box. You may have something there with the idea of trying to maintain the same size air intake, but then you won't be gaining any extra air flow. On my first VT Ascot, I had been given a spun aluminum velocity stack that just happened to fit snugly in the OEM air-box air inlet. I removed the 90 degree angle snorkle from the air-box & cut the base off of it so I would have the original round part that enters the air-box. I used that piece as a glorified grommet & then installed the velocity stack. I ended up cutting the bell shaped section from the velocity stack & inserted that into the grommet. I then radiused the freshly cut end to hold it into place. I hope this all makes sense.
I used to run K&N filters back then & installed the K&N into the air-box. Now the fresh air intake flowed through a marginally larger diameter opening that had a nice radiused entryway. I also removed the square screen located inside the air-box. This along with the MAC dual exhaust still allowed the bike to run with the stock jetting. I had the jetting changed by a shop that had a tail pipe sniffer. Unfortunately I do not recall what the final jetting specs were. I believe they simply went up 2 sizes on each main.
Good luck
J.