Mainline with lunchbox releaser?

[DMF]

Has anyone used 3/4" mainline with a lunchbox releaser?

[maple flats]

Likely some have, but it will depend on how many leaks are in the system. Technically it should work, but only if leaks don't render it useless. You will be best off if you have a recirculation line, from the lunchbox output, back to the mainline, close to the lunchbox. That works best if you install a valve in the recirculation line, you just want to keep the diaphragm wet, not over run with sap.
How many taps will be on this system?

[DMF]

How many taps will be on this system?

I typically run just under 100 taps per lunchbox.

[maple flats]

How well does a lunchbox handle 100 taps, I've never used one. my vacuum pumps have all been gas engine or 240V electric powered.

[DMF]

How well does a lunchbox handle 100 taps, I've never used one.

100 is pushing it. I have balanced my lines to around 90 each.