Welcome to the HIM world and congrats on the first post!!
The first bit of advice I would give you is that your saddle issue may not just be a saddle issue. It might also be a bike fit problem. Did you have your bike fitted by a professional? If not you might look into that. I say that, because the terry butterfly may not be perfect for everyone but it's usually adequate for most. My guess is that either your stem is too long or saddle too far back, or saddle not level, or sit bones too wide for that particular saddle or your sit bones are sliding forward on the saddle, of the wide part for some reason.
As for shorts. I'm a Pearl Izumi girl but my next set of tri shorts will be from Oomph. I'll let you know haw they are when I get them. That could be a little while.
I don't have any personal experience with the larger on top phenom. But some of my bustier friends will simply wear double the support eg: two jog bras under a tri top or a jog bra with a tri top if the top has it's own bra.
I'm sure you'll get lots of great advice. There are a lot of really knowledgeable women on this site.
Have fun and happy training.