Apparently a great deal of players on the lower and mid ranks don't understand how this card's ability works. Ran into dozens of quick play spells and traps that are played after I call my attack. Had one guy use game controller and took almost a minute after it was played to realize wasn't working.
You'll need to learn how to use toggle to master the Tag-Out feature which you can use during your opponents turn. Also, you can chain a tag-out after any effect except negate effects or cards that restrict your tag-outs somehow like Blue Eyes Spirit Dragon and Necrovalley.
Also, I recommend running a card like Lighting Vortex or Needle Ceiling to take care of untargetable monsters and monsters with atk Ulti-Apeleo can't get over.
By chaining Ulti-Canna's Tag Out effect right after the Search effect one, you can get away with dumping just 1 monster in the GY (as long as you can still special summon 1 Tamer and Spiritual Beast).
This site could help you out with combos and stuff. Good luck with the deck.