Hey
@Swamp Dog, don't worry about the flexibility!
Why does your doctor want you to try yoga and what are your expectations from the practice?
In general, I would stay away from Bikram and Ashtanga, and find something that is labeled either 1 or beginners. IMHO, "flow" or "vinyasa" classes don't make a lot of sense for new students, even if they are labeled 1 or beginners, because moving from pose to pose in a true "flow" requires either a very precise teacher for beginners or a student's knowledge base of what the poses are called. Best case scenario is if you can find a beginners series, because it'll build on itself.
If you can get over the anal retentiveness of Iyengar teachers (they are
very precise about how you use props, down to how you fold blankets, and some teachers are not entirely kind about it), it's a really great practice because you are strongly encouraged to use props to make poses accessible to you. Then, the length of time you hold them also strengthens the body.
Sometimes people mistake the Yin practice for "stretching." In some ways it is, but the theory behind the practice is that you are lubricating the joints/connective tissues. In practice, it can be intense - you are holding poses for 5-ish minutes each, and they are not intended to be comfortable. Usually partway through yin classes, I am swearing to myself. I'm an even worse teacher because I see people in discomfort and want to move them out if it...!
Finally, I would encourage you to read the profiles of the teachers that are teaching classes you are interested in. Sometimes the bios are a little fluffy, but other times they can be helpful in getting a sense of where your instructor may be coming from. And remember, some teachers are just not going to resonate with you.
Feel free to PM me or post descriptions of classes if you want help translating.