<<Any suggestions on how I should first announce my intentions when
  approaching the airport.  Since "overhead approach" will not likely convey
  much understanding?>>

You are quite right that most civilian pilots do not understand what an overhead break is.  For that reason, at an uncontrolled airport, my personal assumption is that the break cannot be done if it is going to be even close to a traffic problem.  If the pattern seems crowded, I don't try it and if a problem seems to be developing on initial, I break it off.  I don't assume that any other pilot will react appropriately to what I am doing and assume that all spacing issues are my responsibility alone.  If there is another aircraft in the pattern and I am sure that I can come in without conflict, I do sometimes announce whether I intend to enter the pattern in front of or behind the other aircraft.  If it is in front, I will be at least 1/2 mile in front.  If behind, it will be well behind.  In either case, I am saying that the other pilot doesn't have to worry about me.  I don't think it helps much to talk about my airspeed or path because this assumes that I am asking other pilots to note these facts and do something about them, which I think is too much to expect.  The good news is that a break entry is a perfect way to see where all the traffic is before being committed to the break because it is all right in front of you and you can be pretty sure that, unless someone else is coming in for a break at the same time, there won't be traffic on initial.