I haven't gotten diamonds from the mystical object yet, but I have another chance this time! My first week was in the scrolls tourney, so I had a tough time with planks for a while and am glad it is planks this round. (My boosts are marble-crystal-elixir so my CCs are planks-silk-gems). I make on average 2 CCs per day, which is close to the maximum for a level 4 magic academy. (I got 700 free diamonds from the game early on -- not sure why that happened, it just gave me a banner and said free diamonds -- and used them for some MA upgrades.) My fellowship plays to the bronze level in the spire, and I've gotten diamonds a few extra times there, so I'm now 70 diamonds away from that level 5 MA.
I think having ever-increasing tournament goals (up to a point) is a good idea. My main limiter right now is open provinces, since I am taking a slow and deliberate pace and trying to stay on target for the number of provinces in the chapter chests. Currently I'm at 38 of 50 provinces and will finish chapter 3 within the next week. So I started by trying to make sure I had at least 3 of the tournament province open, then 5, then 6, and in the planks tournament I'm finally going to be able to do 7 provinces. Based on what people here on the forum say, it's probably impractical to try to go more than 10 provinces in the tournament and at least finish the High Halls in the Spire every week. We will see how I do when I get that many provinces open.
I'm passing on crafting planks relics nowadays because the net gain in catalysts by crafting relics is not that great (it takes 3 catalysts to craft enough relics to make 5 ccs, so you only have a net gain of 2 catalysts), and I am holding my own with the MA with the relics I get from tournaments, provinces and neighborly help chests. When I get a level 5 MA maybe I will think they are worth crafting again.