Almost positive that Centurion results in a girthier phallus.
I've heard DHT does work, but everyone I know that's used it has also complained a lot about hair loss. So if your hair is important to you, I wouldn't consider DHT as an option.
Penetration is possible for some guys. Some of it has to do with length, some of it has to do with positioning. You'd have to choose a position that enables penetration. I'm not sure it'd be possible with a male partner just due to anatomy, but it should work with a female. Especially if she's on top.
I did say some though. Not everyone can. If penetration is one of your top three must-have's in your bottom surgery priorities list, I would consult with a surgeon before you make a final decision. All the surgeons I've consulted with have cited a 10% plus or minus change in size with metoidioplasty post-op.
If you'd be saving up for meta anyway, why not just save up for an insurance plan that would pay for whichever procedure you need? I guarantee it'd be cheaper in the long run.