graduation wording-"no really, you don't have to come..."?

Don't sweat it. Unless you are very close to the graduate, or live near them, people understand it's not an invitation to the ceremony. Generally, those are sent out, like you said, to give a heads up...and usually you'll get a gift or some money out of it, regardless if you want it or not. It's just customary...if you don't want some sort of recognition, why send it in the first place? Congrats!

How about sending an announcement that is not also an invitation. Graduation ceremonies normally only have limited sitting so the few people who you want to see you graduation can get a separate invite.

On the announcement you could mention a having a quiet BBQ at home that evening were you would be happy to receive phone calls form those too far away to visit and those who are closer can pop around to toast your success.

Also thank everyone in the announcement for their support during your studies.

Send announcements only, to those you do not expect to come. Send at the time of your graduation, not before. State, "No gifts Please"

Invite those you wish to come separately. If you don't want to pay for separate cards to be printed, then print up invitations on your computer for the ones you want to invite, or call them. Then send formal announcements to all.

It's supposed to be understood that they don't have to come or send anything, even with a formal announcement/invitation. What the recipients decide to do is up to them.

An alternative would be to mention your graduation in a letter. (But if you don't normally exchange letters with these people, the effect would be the same as with a formal announcement.)

Just wanted to share my good news with you. I'm graduating with my Doctorate in ....., and I knew you'd be as excited about it as I am.

tip: send it AFTER your graduation..