I have found this helpful

Here is a link that might be useful: Bath dimensions

Great! Thank you. I have bookmarked that page.
Can anyone who has experienced too little or too much space for two people in front of a double vanity comment?

A jab to the ribs always works for me in those tight spaces ;)

That is a very useful link and have referred to it often.

A 60" vanity is considered minimum for two sinks. This doesn't give a lot of counterspace. 66" or 72" would probably be preferable for two adults . As for aisle, across from a tub will require slightly less because you have some clearance over the rim of the tub, whereas a shower door or wall extends over arm/should height. if you know what I mean.

The recommendation for in front of a sink at the above site is 30" which does not sound like enough space for two people to move around. But then, how much space is too much? We are converting a bedroom into a closet and bath. I don't want to give up a bedroom and then feel cramped in a new bathroom. If we can't create a comfortable space, the deals off. How big is your bathroom, and is it comfortable?