hahaha....I really feel your pain on the dual aircleaners....I've fought with just about every dual quad setup ever made over the years....they get some strange spacing sometimes. You can go to the K&N book for reference, I usually get a top thats the way I like it, with the spin on fancy wing nuts. And I look at the chart to get a filter thats at least 3 1/2 " tall. Anyless, and you get restriction.
This next part might make you wince a little, but its what I do.
Get the bottom that came with the dual quad filter that YOU LIKE, Cut out the 2 necks that fit the carbs on the baseplate. I usually measure 2" off the carb throat dia.'s, cut there with the plasma cutter. You now have 2 circular adapters that will sit on the carbs. Go by Tractor Supply OR Lowes, go to their metal rack, get a piece of 12 to 16 ga. sheetmetal, take it home.
Trace the bottom of the cleaner base onto your new metal, and trace out your circular holes that you cut, f at theor you carb adapters, BUT, TRACE THE HOLES 1" smaller the holes you actually cut.
Now, put on the gaskets, the 2 adapters, your newly cut base plate, the small piece of the origional bottom thats felt with the lip that fits the filter.
Twist, hit, bend, eyeball, measure to your hearts content, getting it all straight, level, get all the metal pieces to fit up exact and really as flat as you can get them. Get your MIG and tack things really light, while all this is sitting on your intake. Now, I do this without the fuel in the carbs, but if theres gas in there, be careful. Get a couple of soaking wet rags and stuff them into the carb throats and be syre to cover th bowl vents, too. Do the same for the bowls and the throttlebodys.
Tack it. making sure to get everything good and flat. Tack a little more.
Take it off, I usually TIG it at this point, but if you MIG it, Pulse it. AKA....stitch weld it, tack the whole thing completely around all the cuts, etc.
Put it back on, doublecheck the fit....it shouldn't pull unless you tried to run a bead all the way around it.
Wirebrush it really good, powdercoat it, Paint it black, dark gray, whatever, put all you stuff on and enjoy.
And that new filter you looked up and fits that base....write that Part# down in a little notebook and keep it in your toolbox.
I keep a cheatsheet in my wallet, with the oil, plugs, filter#s, for all my vehicles in there, so if I need to pick something up, its always with me....