I've built a lot of dirt track race car wheels by purchasing blank wheels without centers, and machining/welding my own centers made from flat steel plate. If you can do a good job of fitting and welding the centers into a tubeless wheel, go for it. Just be sure the welds are good quality, with the right alloy rod and good penetration. I used to use a magnetic-base dial indicator to check for runout after making a few tack welds. If everything was OK, then I'd weld it up all the way.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!