I weighed 275 when I started hormones. Since then I have had noticeable growth, but I'm not exactly a D cup. Some people are just late bloomers. You never know, you may hit a growth spurt this summer and fill out. It's like planning for an earthquake. Not possible.
As for the bulge, I understand that fully. You probably won't believe this but I swear it's the truth. Erect I am 9", and very thick. I have to wear 2 panties, and constantly readjust to have any attempt at keeping it hidden. I did consider duct tape, but that would be both uncomfortable, and hurt like hell taking the tape off. And what if you suddenly had to go in the middle of the day? How would you maneuver around taking off and reapplying the tape? Not very practical in my opinion. But dresses help a lot to hide captain winky. It's a trial and error thing. Good luck.