I've got to say that I have done exactly this, but it hasn't gone at all well. I have spent several days building admin sections with DataAssist, and it's not working at all.
Basically, security assist is causing me all sorts of problems on the pages where I have used a template of my own based on the PCMS Builder admin template. Everything I have done over the last few days is now being deleted and built again. Even though I am using the security assist settings built by PCMS Builder, the pages will not load even though I am signed in!
All I can say is try it, but be prepared to throw a lot of work and time away!