This is the current build with another post to follow with pump details.

Bunnings plastic bird bath for $19

 
Instructions – only needed a glance lol. Yeah… happy with the purchase.

 
We need a overflow outlet. Went through all my water fittings and and came up with this one… hmm

 
Cut off one side with a junior hacksaw and then smooth off on the disc sander.

Drill out the hole as much as we can to increase the outlet flow.

 
Measure up for the hole size to drill and a 20mm Forstner bit will do nicely.

 
Bore the hole. That’s a nice press fit; should be able too try that out now and glue it later,

For that outlet I had to turn the pump to minimum flow to equalize water in vs water out. See next post part 3 for pump details.