I view Group Builds as an e-version of a kind of modeling club meeting/build "night".
Everybody sitting around and building, swapping info, making silly comments, teasing, praising and showing new or renewing old techniques, to the other guys. This environment brings out to best in each participant. While allowing for a friendly supportive atmosphere to keep the"lone-lys" at bay and create a sense of shared purpose.
Benefits? all the participants and those who follow along 'incognito" increase their abilities and knowledge of the subject matter.
Cut to a specific length of posts? No! Counter productive.
In current WIP threads there is no limit of threads even those that start and stop and restart maybe months later. Yet there seems to be no problem with those threads. Nor for those that stretch out, sometimes for over a year ( due to some real world interference) or are heavily laden with "how to" photos causing a large number of posts.
Ours is a dynamic as well as a tradition laden (hidebound, some may think) hobby, never staying in one place too long but evolving from a basic interest in creating a product that pleases us and sometimes,if so inclined, being able to share with like minded folks that appreciate our efforts.
Gotta go now, my glue is dry and I need to get the prime coat on........