Did you watch the lottery video on MSDC? It explains the master number element which is the most important thing to understand about the lottery.
Basically if you get a great master number you will get in wherever you want; if you get a bad master number you won't. The good news is that with twins you get 2 chances for a good master number.
The schools where you have "no chance" for Pk3 are Brent, Ross, Stoddert, Van Ness because IB students will take all the seats offered.
You have a better shot than most at Maury (bc IB and twins), School within a school (bc twins) and as good or better a shot as anyone else at any of the charters you are probably interested in.
Info sources:
For curriculum info, start with the DCPS school profile pages. For charters it's school by school.
DCPS WL data / includes initial results for IB/OOB/Siblings
http://enrolldcps.dc.gov/node/61