I think rather than selection token.. it should be form.tokTime.earliest and form.tokTime.latest to be overridden with selection earliest and latest time. I have this explanation in the other answer as well. Selection just filters the events where as Drilldown re-runs the search with the selected values. That is why I had coded a drilldown to generate URL required where tokTime was overridden with selection time. Your option would be to code the same using JavaScript.
Here is an older answer for saving user selection to a lookup so that it loads with selection when next user logs in. May be you can explore this as well: https://answers.splunk.com/answers/617305/how-can-i-give-the-to-the-users-to-save-their-sele.html
But if you are using JavaScript, then you can better code Selection behavior directly in the code rather than using this option.
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