I must say these last few threads about the overhead have been an interesting read for me, I never knew it was such a big deal. I come from an almost all military training background and the overhead is basically the default entry to any pattern, formation or not, towered or not, heck, even for us non-fighter guys. I flew all over south-east Texas in a King Air for the final portion of my flight training, we flew patterns at just about every airport we could find, and flew the overhead into all of them with no issues at all. Maybe people were used to us, I'm not sure?
I fully admit that I am bias on this (we all like what we are familiar with), but I think the overhead is the safest way to enter a pattern, especially when entering a pattern with disimilar aircraft. I think everyone will agree in formation the overhead makes sense, but I would argue even single ship it does, and I will try and explain what I am thinking/looking for when I enter the overhead.
-Initial (3-5 miles out on landing runway centerline) - At this point you should start getting eyes on any traffic in the pattern. Hopefully you have been listening to the radio and built a picture in your head were all the traffic is and they should be easy to find. But this also gives you a good view to find anyone who may not be talking on the radio or simply not making the correct position reports. This is also were you look to see who might be a conflict, depending on the speed of the aircraft in the pattern. It is usually the people who just turned downwind (slow guys), are on crosswind (normal), or the ones on the runway or just took off(fast guys).
- Approx. 1 mile from the numbers - At this point you should be able to tell for sure who is going to be your conflict traffic and you can plan accordingly.
Just follow one simple rule when planning the break, ALWAYS GIVE THE RIGHT OF WAY TO ANYONE ALREADY IN THE PATTERN. There is no reason to cut anyone off (even the slow guys). If there is someone on downwind that will be a conflict simply extend upwind, on runway centerline until proper spacing is created. I generally use 45 behind my abeam as a starting point, if the traffic is slower I will wait longer, if the traffic is faster, I will break as early as abeam me. Nothing says you HAVE to break at the numbers or by mid-field, I have often had to wait until the departure end. Worst case, there are multiple people on downwind and you can't fit a break in by the time you cross the departure end, well, this is the beauty of the overhead, you simply turn crosswind.
If done correctly, the overhead should never mess up a pattern, no matter how busy it is (works at UPT with up to 14 student pilots, some solo, in one pattern at a time). But, as the person flying the overhead you have given yourself the most options (can enter the pattern by breaking anywhere on downwind, or worst case on crosswind), and have keep up enough energy that should something go wrong you at least have a fighting chance at using those pilot skills to get the plane on the runway.
Also, one random tip for those just starting to fly the overhead and want to create good habit patterns, always start the break FIRST then pull power. If you ever fly formation this is very important.
I know this was a little long winded, and hope it added some value for those who aren't used to the overhead. If I just made things more confusing, or if anyone has a question please let me know.