Ahhh dang. That makes it a bit tougher then.
I'm a hobbyist at TT and if I did do an event everything is close enough I'd be fine for a USAC race. Shoot, even obviously "tri only" stuff often is in the slower fields.
Good luck. That's a tougher formula to crack being within that UCI scrutiny.
How much leeway do you have to using a UCI legal base bar but perhaps having "custom touches" to get extensions the way you want? Like if you modified off-the-shelf clip-ons to get them lower? Or you had a machine shop make your clamp for the pads/extension?
I've no idea. It would be interesting to know. I thought the big boys pretty much had to use stuff "available" for sale within 1 year. But, you often see custom little touches on bikes it seems.
Let us know what you wind up with.