How to set and parameter Silverfast

Hi everybody,

I’m currently using a flat bed scanner Epson V850 with wet scanning Epson as well.
I’m also equipped with silverfast 9 Ai Studio.

My question is how do I have to parameter the silverfast 9 Ai Studio ?

Do I have to set Transparency: Holder ?
or
Do I have to set Transparency : Glass ?

I would greatly appreciate if someone could help me how to use these devices listed above in order to get the best results.
Many thanks for your help and consideration.
regards,
Dom