Interesting links, especially the one about cervical vertigo.

I tried to get a dopler ultrasound of vertebral blood flow but the tech refused to do a comparison of neck straight vs neck turned.

I doubt an MRI will make a difference because the radiologist would need to believe there can be a problem. Plus, MRI's are not precise enough.

Better to just find the upper cervical chiro and see what he/she finds.

As I have said many times before. The most important part will be your postural discipline, especially during rest and sleep so you do not undo any improvements made by the chiro.