50 grams of powder?  I have no clue how much that is, but it sounds like a lot....  Usually you only need 1-2 tablespoons of powder.  If you need more then that, then the powder probably isnt San Pedro, or it has something else mixed in maybe....  I dont know, but...  Every San Pedro powder I ever saw had a dosage size somewhere in the 1-3 tablespoon range.  (is 50 grams about 2 tablespoons?  I never weighed it before....)

If you decided to make a tea with the powder I dont see any reason why it wouldnt work....  Should work fine as long as the powder is active.  Probably do it just the same as when you chop it up small.  Might even get a more effective extraction since the powder is so refined already.  Probably more work to strain it out, but you should manage.