Bypass hose is 3/4”. It has a camlock connection so that I can disconnect it when winterizing, and I don’t end up with antifreeze in the bottom of the tank.
Bypass line goes into a 3/4” or 1/2” bulkhead, IIRC. I just used an appropriately sized barb-pipe thread elbow to connect the hose to the threads. I also have an elbow on the inner side of the bulkhead, which directs the flow against the side of the tank to eliminate bubbles.
My supply reel has 1” internals, and I have 1” hose going from the reel to the float valve.
I also have camlocks on all my garden hose, and camlock fittings tee’d into my supply plumbing, so I can do like @redjess and bypass the reel when needed, or even dual feed from two different spigots.
My hudson valve doesn’t have its own bulkhead. I just cut a hole in the tank lid large enough for the neck of the valve to stick up through (I used hose clamps to hold it up). That way the tank fills to the brim before shutting off. Got the idea from @SchertzServicesLLC.
I really need to shoot a video of my plumbing setup someday. It’s a bit much to try and describe in writing.