since it is only for 20 months, I would say hardcode the dates in a schema and use it against running the workflow
write a JS that skips on the 2nd and 4th Saturdays for 20 times.
Really appreciate your effort, I checked once again and found those observations::
Kindly have a look.
For the option one(Hardcode dates in schema): Yes, We can select specified date but only one but we can't select multiple specified dates.
For the option 2(Writing JS): I want to do so in the workflow and after using scheduler, and there is no option of writing JS inside scheduler.
Still curious to find solution of my problem.
You can achieve so by selecting a scheduler to run weekly and then a test condition: is week ==2 or week ==4. If it satisfies the condition then execute your workflow else end it. Within scheduler you can mention about number of iterations this workflow should run.
Test Activity is present under execution activities while configuring the workflow as per the help document. But I check it so while configuring the workflow. I am unable to discover that "Test" option under Execution Activities.