I definately have to wait for the t-stat to open.. when it does it is a nearly instant rush of fluid out of the tank and into the block. The bleeder valve may trickle coolant in, but when the t-stat opens, you know it.

I keep a close eye on the engine while doing this, I know how hot it should be and how hot is too hot. You can't trust the dash temp guage.

Works for me just fine, and I don't have to bleed the block or jack the car up..