So its been a minute but I have finally been able to pull together some dimensions.
The bell siphon is -11 1/8 in (1-1/2" id)
also, one more picture! actually, two more! by the way, that aerator didnt stay on top of the bed past taking the picture... Also, all pipes are 3/4" except for what comes out of the actual fish tank. If memory serves, the fish tank is fitted with a 2" SLO that goes out through a bulkhead and then hits a 2" 90 that changes into a 2"-3/4" reducer.
One problem I have been having is that as I adjust the ball valves to try and get the siphons to kick on or off, suddenly the fish tank will be overflowing and I have to scramble with a bucket. As much as I need the cardio I dont think this is how this is supposed to work. A friend recommended capping the original spot, then dropping it down a bit? Id have to maneuver the grow beds too, but does anyone have thoughts on that?
Lastly, after adding a third picture, do you think at all that the teeth of the bell arent deep enough? I had pretty much this exact set up earlier in the year so Im hesitant to go a bit deeper. Anyways, thanks again everyone!