It just so happens that I have habaneros in the keg right now. Are you bottling or kegging? If you are kegging you can just throw them in until the beer is to your liking and then pull them.Kegging. I assumed a tincture would be more measured. Can you expand on how you pull them? Are you using a bag, or are you transferring to another keg to rack the beer off the peppers?
I have had the best luck by dicing a deveined and deseeded pepper then putting it in a muslin bag that is to be suspended in the keg by plumber's tape. I was lazy this time and did not dice the pepper, just quartered it. I may have to add some more to speed up the process.
A tincture would definitely be more measured but I find this easy because I can taste it every day to see how the flavor develops and halt the process when it is perfect to me. Also, I don't have to worry about measurements for future batches.