Preface:

Please skip the "If you don't know you shouldn't be in there" comments. Asking this about a home that I am building for myself. In HVAC but not an Electrician. Also, I know this is a well documented topic, and I've tried to read other subs/articles but nothing has clicked for me or answered my specific question.

Here it is:

My meter base only accepts a ground connection on the neutral connector. Does this mean that, even though the breaker panel beside it will be the only one for the home, it should be treated like a sub panel? 

In that case I need to remove the strap connecting the outer bus bars, separate my EGC's from neutrals and put a bonding screw in the ground bus bar, leaving the jumper from the bonding point at the meter base to the ground bar in the panel in place?

I consulted with a licensed electrician about this; he told me to remove the ground jumper between the meter base and the breaker box. Then, allow the Neutral and EGC's to share the bus bars, and use a bonding screw there to the can. This method does not seem correct, but I can't define why. Before I go back and rework the panel I need to understand.

As I said before, I am in HVAC , so I work with some circuits, but I'm stumped about understanding parallel return paths. (Should probably be more well versed in this for my own trade.) I know that the golden rule is to only bond the Neutral to the Electrode in one place. What will happen electrically if the Neutrals/EGC's end up on the bus bar together?

Is My "Main"/Only Breaker Box A Sub-Panel If Neutral Is Bonded At The Meter Base?