herbie on RR tank?

[75gal]

I have an 80 gallon SC aquarium that has 1x 1" and 1x .5" bulkhead fittings...I'm told I souldnt expect more than 400gph through the the durso style with 1" I know I can supliment with DT flow but if I go with the herbie method using the 1" for the emergency wouldn't that be even less flow? I'm just trying to figure how many holes I need to drill in my stand before I place the tank. Reason being if I go herbie I'll need an extra hole for the return. Thanks
Tom

[MCWRT]

Tom... Just finished a basement sump herbie drain on a 60 cube. I had two one inch bulkheads. I ran the return over the back. Marineland states their durso standpipe is rated for 700gph with a 1 inch bulkhead. Since both bulkheads were 1 inch I used a 1.5 standpipe for the emergency with the same 1.5 inch diameter on the return line to the sump. The emergency easily handed my iwaki running around 500gph. The siphon used a 1 inch pipe and a gate value and I swear it is probably open a full turn at best. The fact my drain falls 11ft is a contributing factor in how much flow the emergency drain can handle. Obviously every system is different but having just finished my a week ago the most important important part of running a herbie is the water test. Testing the pump of full power, full siphon closure and loss or power and subsequent siphon restart.

The guy who convinced me to do my herbie used a herbie on his SC 90g with great success.

Best of luck!

PS herbie is totally worth the effort!