1. That would depend on the data to be put there, the structure of the rest of your data model and the design of your user interface. You run a very real risk, however, of simplifying the look of your relationship graph at the expense of complicating the function of your database and the process you have to follow when making future design changes.
There are other ways to simplify your graph. The ExecuteSQL function and Anchor Buoy come to minde.
2. Tab controls can help divide your layout into sections and the tab control can be invisible with a script used to control which panel is the front panel and thus sections of your layout can appear and disappear.
But upgrade to 13! the slide controls and (even better) popover buttons are a major improvement over what you can do with your layout in version 12.
I will ponder all that advice.
FM 13.....lots of useful additions from FM 12.......I was rather hoping FM 14 was due within 6 months? Guesswork I know!
And guesswork for which I have no answer. If I knew, I would not be permitted to tell you. But in this case, I don't know and FileMaker doesn't tell you in advance of their new releases.