Assuming you are using the default layout:
Edit the Blinds cell.
Create a new Property Group. Name it "Round N" where N is the first round where the blinds need to be a smaller font.
The Odd Rounds property set will be selected.
Uncheck "use global property set".
Change the font size.
Repeat for Even Rounds and Blinds property sets.
Press the Conditions button.
Enter "N" into the "Round:" input, where N is the first round where the blinds need to be a smaller font.
Press OK.
Create a new Property Group. Name it "Round N" where N is the second round where the blinds need to be a smaller font.
Press Copy, then select the property group you created in the first step.
Press the Conditions button.
Enter "N" into the "Round:" input, where N is the second round where the blinds need to be a smaller font.
Press OK.
Repeat for each round remaining in the schedule.
In a future version, you'll be able to simply create a single property group and set the Conditions to "round > N".