Hi Lola. Welcome to the club of the genetic males growing boobies.
And welcome, from my side, to the club of non-transitioning CDs with accepting wives (well, mine doesn't know about PM...).
About dosage and stuff: 1000 mg is a decent amount to start. Some people have results from that, and it's the dosage given to women to keep their skin healthy and their hair thick. It won't hurt you.
Testosterone is not going to stop your development per se, but it will slow it down. Many people here take some form of T-blockers to get it out of the way but many, like me, just let it run so they are able to perform with their wives.
Breaks are particolarly useful at higher dosages or if you notice lack of libido, hard to maintain erections, fatigue, bone pains, or if you overdose. At 1000 mg/day if your body doesn't give you troubles then you may not need breaks.
Depending on how serious you are about growing, you may want to push the dosage a bit higher. The physiologic limit for a healthy male seems to be 3000 mg/day, but you'll have to ramp up slowly to get there without causing harm to your body. If/when you bud (give it a good 3 or 4 months to get there with or without testosterone), a couple of months without T and with something like 2000 mg/day should really do some magic and give you some initial shape.
Goodluck with your journey. Pictures or no pictures we're all here to support eachother so feel free to ask, message and browse around for more info.
Shiraz