Big Agassiz is...well...big. Certainly in comparison to its little brother on the hill top.
Climbing here is dependent on a number of factors. For starters, being much lower-lying, the ground around Big Agassiz is debilitatingly swampy in the Spring or after rains.
At my last visit, there were some decent looking toprope anchor bolts. Inspect them before committing your life to them. Some clean gear backups may be available. Bring extensions.
No named routes are really spoken of here. One face of the rock is the most vertical and has the most potential. Check it out.