Posted these a few moments ago as hose valves. Read the fine print and they contain lead. Back to Walmart for the plastic version for about three bucks.
Most of these small ball shutoffs have small internal size that restricts water flow a little, but the flow rate may still be ok. That is the same reason we do not like the small end of hose pressure reducers.
I noticed the restriction and not sure how much it will slow filling tanks. I hope to create a gravity feed as you have described in a previous post. Hopefully they will allow a convenient way to insure the hose does not drain into the bay. The pressure regulators seem to be off the table with the gravity feed.
This chart may help you on how much water you can get through a hose at different pressures.
Water Discharging through Hoses (http://www.engineeringtoolbox.com/water-discharge-hose-d_1524.html)
John