Similar to the previous reply, when I build rings with greater than 24 segments:
1. I use glues with extended set times, allowing for longer assembly intervals, such as Titebond Extend.
2. After a dry assembly to confirm the positioning of species and the absence of gaps, I mark the tops of the segments with a sharpie to identify my glue-up plan. This keeps me on track with my glue-up plan.
3. I execute the glue-up plan which usually involves iterations of selective pairings followed by clamping the entire ring together to dry before all the segments are glued. This spreads the glued segments out fairly evenly such as glueing every other pair in the first round, or every third segment to its neighbor, then tightening the hose clamp to dry then doing the next or remaining segments for the next or final round.
A note of caution: the dry segments will move differently at hose clamping than when glued. It is important to assure all segments are positioned properly AND that the diameter of the clamped and tightened ring is the same when checked top-to-bottom and left-to-right as well as other checking points so that the partially glued segments when dry will still form part of a perfect circle. Otherwise, the partially clamped segments may contribute to a slightly oval ring which may destroy its usability. With large segment counts, you can never rely solely on the hose clamp tightening to bring the segments into a perfect circle, even if you are fast enough to glue them all at once.
If you discover the diameter varies when measured at different points, how to fix? Loosen the clamp slightly and manually push together the sides where the largest diameter is measured then retighten and recheck. Repeat as necessary until the ring is perfectly circular. If the glue has set by the time you do this, you are trying to glue too many segments at once. Trust me, taking your time to glue rings in perfect circles will save you from having to recut and remake rings that are not usable!