Thank you, all of you, for the awesome info! It helps to know where the common problems are. I will investigate further.
I was using a water hose, but will do it again (once things dry out) with more precision.
I can say that the channel us not filling up and overflowing. I will look for a route out of the channel to the interior, that should not be there.... or find that the water invthe channel is a watery red herring and the real leak is elsewhere.
I didn't think enough before, but realize now that if water is coming in between pane and glass it is going into the channel, and SHOULD be directed out again thru the weep hole, so that system is what matters.
3/4 timing in a DIY van conversion. Backroads, mountains, boondocking, sometimes big cities for a change of pace.