My baby A was head down until 30 weeks or so... then she flipped. I tried a few things to get her to go head down again - chiropractor, hanging upside on monkey bars, pelvic tilts, hanging inclined on an ironing board, yelling at her... she stayed breech, then I got pre-eclampsia and had them at 35 weeks. C-section. Oh well! Really wasn't half as bad as I feared, for what it's worth.
At 24 weeks there's just too much room in there to worry yet... baby is going to move around a lot still. Good luck! They can flip either way at any time... little stinkers.
Personally, my health took such a disastrous nose dive at the end I think a c/s was best for me. Had that not been the case, though, i think that rather pleading with the baby to go head down again, I wish I had looked harder for a practitioner who will do a breech delivery of baby A. Even if it hadn't been a good idea in my case, it would have been nice to have someone open to it. It's all well and good to try to get the baby to be in the right position, but a practitioner willing to work with what's there is worth a lot, too. Sometimes a c/s is best but I wish more practitioners were willing to attempt a breech delivery. There are women who have had vaginal deliveries of a breech baby A successfully. For me, I just kind of accepted that Breech A means C/S...
But FWIW this is the site I tried to get some info from.
http://www.spinningbabies.com/
The hanging off the monkey bars was my own idea, though, and that was a feat. i thought it might kinda jar the babies into moving around but it was really just idiotic, hanging there in the dark with 15 pounds of uterus flopping in my face. I don't reccomend it.