Hi Musicnabber!
To me, your problem sounds doesn't sound like one of flexibility, because you say your back leg always bends. You don't mention that your total look is one of a V-shape to the legs versus the legs extending closer to 180 degrees apart.
If you back leg is bent, I'd say your problem is one of extension of the back leg. Assuming that this happens on both sides, I think you may be more concerned about your next step than the full extension of your back leg.
Think about it. If you grand jete forward with your right leg, with the left leg back, although yopu land on the right foot, that left foot has to come quickly forward to move into the next step. If that back left leg is not fully extended, it sounds like you're already planning to bring it down for the next step rather than continuing to sustain the extended back left leg to complete the grand jete.
There may be a matter of height involved, for if your grand jete is close to the floor, you are going to have to move the back leg forward more quickly for the next step.
I would say concentrate on extending the back leg by sustaining it for as long as possible before moving to the next step. After all, you're going to land on the forward foot in plie, so you have enough time to bring the back leg around.
Regarding development of good male technique, you say you've been taking ballet for about a year. Good male technique does not really become a factor until after you've built a solid base of ballet technique. It may be too soon to worry about developing good male technique.
I hope this helps! balletboy[/i]