Not necessarily storm, tho sometimes it can accidentally happen :^). Personally i've found the correct balance to be 30 defenders. To generate more cantrippy value i love Cloudstone Curio, it's especially nice with shield sphere.>Since I do want to still somehow win if I get Mindslaver'd and Arcades gets proper exiled
Understandable, tho i would advise : better be preventing than healing. I wont lie to you, if arcades can't stick the board, the deck usually become pretty shitty. In bant you have all the best options to protect him.
I made a list for you of the best protection availible in the colors :
Mother of Runes
+ all the counterspells.
Personally i prefer mom, safekeeper, yavimaya hollow, greaves (obviously) and steely resolve. This way you have protection in form of creatures, artifacts, lands and enchantment, pretty nice to avoid being too sensible to various kind of removal. 4/5 protection cards, alongside a nice little suit of counterspells should be enough to stick your dragonfu on board in safety.
Another safety option is simply to generate a lot of mana, which walls are surprisingly good to provide. So don't hesitate to run all of the mana producers ones, alongside bird, craddle (if your budget admit it), cultivate, rocks and so on. It's not an issue to cast it 2 extra times from the CZ, it become tricky only when you reach the 10+ casting cost.