Unsure which method to use

[undeath]

The attack looks good, especially for your use case. One thing that ruleset does not do is toggling the case of characters. You'd have to chain together with toggles{1,2,3}.rule to include some case toggling. Chances are, one of your leetspeak modifications is not listed in unix-ninja-leetspeak.rule. In that case you can try with Incisive-leetspeak.rule which has a few more rules, again while chaining with the toggles rules.

Chaining rulesets simply works by using -r multiple times.