Hi davemax. I am going to do the same think except I am going to use Great Stuff and xps rigid foam. The batt insulation will cause mold to grow it is not a good barrier. In some states by code batt insulation is not recommended.
My other thought is to have the areas professionally spray foamed for a more secure insulation, but I am concerned about off gassing.

Here is a response to the same question to Owens Corning: any thoughts?

We would recommend using unfaced cut-to-fit pieces of insulation and place them snugly into the space.

Fiberglass insulation does not contain water or a food source. Mold requires a food source, warmth, and moister to grow, none of which is provided by the insulation.

Best Regards,
Jill Laskey

Owens Corning Get Pink Team

I understand what they are saying, but...I have done a lot of research on this and including on these forums rigid foam seems to be the way people are going with this. You can check out some great videos in you tube also. Can we know for sure our basements have no humidity or moisture issues? I know I have to run a dehumidifier in mine in the summer, but over all it is pretty dry. The other issue some folks have raised is even with the rigid foam you have to make sure it is pretty tight so that moisture does not build up behind it and cause rotting of the rim joists. So much to think about. That is why I may just go with the spray foam despite the cost. I have some pretty big holes where the vents are going through the floor. I can feel the cold on the floor in my living room and dinning room. If you google rim joist insulation you will find a lot of information and videos.

I remember when cigarette makers advertised their products on the recommendations of doctors.

The fiberglass does nothing to stop airflow and condensation so mould still grows on the rim joist wood.

See Building Science Corp. for the recommended methods of insulating rim joists.

Moisture can still build up behind the rigid board in the joist as well and result in mold on the joist. and if the joist is caulked sufficiently prior to putting any insulation in there, that could eliminate the air flow.

Yes davemax, that is why I am considering just doing the professional spray foam only and not the rigid foam + great stuff.