Welcome Jack:
The Creek is a great place to learn and share info. Hope you enjoy it as much a I have.
I'm not familiar with the overarm design you mention, but will share one that I have used for a couple of years.
Warning: it is not pretty, but it works very well.
The third shot is with the overarm raised to clear the cross-cut sled with a similar dust collection concept.
Hope this is helpful. Best regards and welcome again, TJH