Set the default value of a NoYes Enum to Yes

Hello Experts,

I have a query. I am creating an extension of standard table & form. There I am adding a new enum of NoYes type. In the method initValue of the table I am setting the enum value to be Yes. However I see for the records which are already present in the system ie demo data for USMF the enum value is set to No. I want this to not be the case, and have the value of the enum defaulted to Yes everywhere. How can I achieve this? Also I see that the enum field is a drop down. I want it to be a slider, how do I achieve this?

Any help would be much appreciated. Thanks in advance :)