Honza did some measurements of the difference between spider, anchor buoy, and selector connector on a large solution.
Graphs with lots of paths (or maybe it’s really long paths) take longer to resolve when a solution is opened by a client. An under the hood session that touches on that would be cool for sure.
Honza found that by changing his graph from spider to anchor buoy, their solution could initiate a PSOS session 3.5x faster. Furthermore, when they added a “connector” table and linked all the anchor TOs, the speed gains were immediately reversed back to the original slow spider speed.
So I’d venture that anchor buoy is the way to go to preserve performance as a solution grows, ie more discrete TO Groups, even with some relationship redundancy, is more performant.
A link with more info: Arachnophobia at FileMaker Konferenz 2017 | 24U Software
I believe Honza’s slides are posted somewhere as well.