"How many leaf sets on the laterals can I expect before I get a bloom."

If it's the same variety, count the leaf sets of the blooming one for your answer.

Some varieties naturally grow laterals early, and topping doesn't help much. Your varieties might be in that group.

Okay. Most of the poms have 2 to 3 leaf sets before the bloom appears. So far, I have noticed that topping makes it bushier. The laterals are much thicker on the topped ones. The untopped is leggier. Is there really a benefit to topping, or pinching, rather?

2-3 leaf sets? Sounds like bedding dahlias, or that there are hidden leaf sets under the soil.

The benefit is just as you described. The plant focuses on the structure instead of the propagation. Typically, this gives you more branches sooner, and a larger flush of blooms at one time instead of scattered.

Oh. I meant on the lateral there are at least two leaf junctures before the central bloom at the top. The sets are quite stretched out so I am getting very long lateral on the one that is blooming. The blooming plant itself is about 3' tall.