Would it be better to just make home-made swerve drive things for the knobbys wheels using 5 X 15 or 5 X 25 or would it be better to ask vex labs to make something like that just wanted some opinions
If you want to use the knobby wheels make your own.I think the best wheels to use with swerve are omnis or all purpose.
Using the “knobby” wheels on a swerve drive sounds like a weird idea to begin with… Why would you want to raise you CG (Center of Gravity) even more than it would be with the small green wheels? I would make my own wheel module brackets if I was you though. Just get some sort of sheet metal (7075 Aluminum probably) and cut it to your desired dimensions. Just be sure your hole spacing is good so your wheel axles and motors do not get messed up. Good luck!
“Bigger” isnt always “better” 
I was surprised vexlabs made a bracket for swerve drive in the first place. I personaly dont want to see them introducing products that we can already effectively make ourselfs, but rather products that increase the ammount of different things we can make. Such as the new gear kit and the larger omniwheels.
i always vote to build your own over using a pre-made kit…
~Alex~