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The Data Canvas is a great place to manage, wrangle, cleanse, and enrich data. However, the options for formatting column data types are not found within it. You must leave the canvas and go to the Data Panel column handler then select the gear icon which is all somewhat un-intuitive.
I suppose my trouble here is primarily between navigating back & forth. If the existing Data Panel could simply be made visible/interactive while the Data Canvas was in view, it would mostly resolve this for me.