Went through this with my partner four years ago. We're in Cali so we went with Keiser so we could go to one hospital for all the doctors and specialists and therapists and surgeons who had to sign off on transitioning [things might be easier now, or difficult depending on where you are].

So with KP, we chose the highest plan, but only for the year when the actually surgeries happened. All the appointments leading up to surgery were covered well enough on lesser plans--and would cost essential the same under higher plans--but the surgery itself was 5000 dollars under the second highest plan, and only 300 dollars under the highest plan. Of course, the highest plan cost us an extra 3000 dollars that year, but still we saved money doing it that way (but only for that year, then once the surgeries were done we switched back to a lesser plan the next year).