Parameter Optimization for non-numerical variables (GINI vs Gain) Workflow Example

My apologies and this seems like a pretty straight problem I’m having but after watching several YouTube videos, workflows, self-paced courses I’ve come to this last option. I’m trying to set up the Optimizer Start/Start Loop for a Tree Ensemble model and as long as the variable is an integer I’m good. However, I’m interested in including Split Criteria. When I add “new parameter” to the Start Loop, I make sure to uncheck “integer” and have attempted to fill in what I think the node is looking for but it will treat it as an integer no matter what. I see “Split Criteria” as a Flow Variable Option so I’m thinking this is possible but I also did read a post where it seemed including check boxes and strings into the Optimizer is pretty complicated.

Any workflows showing how others have achieved this would be greatly appreciated (including check boxes as I’m sure someday I may need this too). All the videos and workflows I’ve reviewed only included numerical variables. Thanks!