i'm way late to this thread, but i figured you might still want an answer.
As pwnisher said, the circus db is truly entirely differen from what you're doing here. The mass of the db makes it so much different. your positioning wouldn't work the same way as what you're doing here, at all. So it would be a completely different movement.
I've also seen heavier i local shows. More like 130+ for pretty much every local show I've seen in this class. But different promoters favor heavier weights in some events more than others.
Your hold at the top was fine.
You can't like drop the weight after each rep, but touching the ground very quickly with it is perfectly acceptable. In a race for reps, they expect it to be moving fast.
If this is all you have available to you, I would certainly train heavier as you're able to, because I think training heavier with a regular db will translate to a lighter circus db.