Ok, thanks for confirming my suspicions. I've developed an algorithm for non circular transfers. The basic mechanics is relatively simple, alg-trig formulas, but there's no way to solve the system of 5-6 equations I get. The transcendental trig functions make it so. Time gets a little complicated, too. The orbiting craft has to travel partly around its orbit, and then around the rendezvous ellipse. This time has to match the time of the target in orbit. The series expansions relating time and true anamoly, or numerical integration (which is just a simple series with lots of terms) work.
My process has been this: given the positions of orbiter and target, determine where the orbiter burns and with what delta-v. I choose a position ahead of the orbiter in increments, then choose increments in delta-v for each position to determine an ellipse that just touches/intersects the target ellipse. Then, check the time of flight of both objects. If times match (are close), then done.
I've tried working tangents (derivatives of polar positions) into the problem, but that fails because equal tangents don't insure intersection.
Anyway, I've got an iterative procedure that working. I was just wondering if anyone else here has attempted this, and it seems so. There's supposedly a third degree differential equation that's really efficient at getting the solution. I've read a little about the Lambert problem, but I was trying to solve the problem myself, from scratch; just basic principles.
Another note, too. Excel sucks for this type of heavy-duty number crunching. I had to put in error catches because dumb excel truncates floating point numbers due to its rudimentary bit scheme. Have to do this in a real math language.
I've enjoyed solving this problem by myself, with only basic principles (mechanics, etc.). Now that I've done it, I'm curious to see what other folks have done. I'm relieved too, to know the solution is not closed form (trivial). The drawback of working alone is the almost insane, or obsessed state it can put a person in. I imagine this is how some of the pioneers felt at times, Kepler for sure. Thank you for responding, and thank you for the links. Very appreciated!