Well I never really solved the front heater issue and decided against tearing the dash apart for time being.
Shortly after that I discovered that my rear heater works amazingly well and pretty well compensates for the wimpy front heat. Other than me and the wife getting cold feet the van stays toasty warm thanks to the rear heater.
So that kinda tells me it's not a coolant/eng temp issue. I know it's not a blower problem because when set to cool/ac there's plenty of air flow. So back to 'blen gate' and/or 'clogged heater core' meaning cogged with debris restricting air flow through it is what I suspect the problem might be. When I first purchased the van (used) I noticed the cabin filters were badly clogged with leaves, some might have gotten past the filters!?
Witch means ripping the dash apart!
So. Rear heat suffice!
I'd also be interested in any insights, follow ups ect...
Cheers