What about cutting sharp vertical notches into the back edge of the seat, it would help the CFM and induce more turbulence and shear, could even cut them at an angle to increase swirling. One of the key points is why do we need tumble port and swirl port design in the first place? Poor design. The manufacturers designs have to try to get a homogenous mix for best combustion= power=MPG= cleanest emissions, for cheap.The pretty pictures of fuel injectors spraying a fine pattern do not translate when shooting down an intake port and it does not matter how big the port is it is still too small and causes the fuel to condense on the wall falling out of suspension as seen as by the "clean" spots where the fuel is hitting the port wall. Velocity is the helper to keep the suspended gas in the best mix for all of the above, and the sharp edge of the back of the seat is an easy way to help poor head designs which are caused by trying to make the part cost low. One of my old bosses was a retired VP at Ford and we would talk about best theory VS cost, I was young and dumb and not even into Fords at the time but the business truths are the same for all big car makers he would show me. Back when I was building big block Mopars the ports and head flow was huge, air speed was not with big carbs, big cams and a great way to reatomize the mix was to use intake gaskets that had fine mesh screens molded into them, cut down the CFM alittle but the liquid gas went back into suspension and lit off better=more power, which is counter intuitive. Which brings me back to building a high compression, close clearance set up for a NPI?