WHAT IS THE RECOMMENDED ATTACHMENT AND SETUP TO CONNECT MY ROCNA ANCHOR?

In regards to Bow Roller compatibility:

1. Any roller designed for a Delta will typically work well with Rocna as the shank profile is similar.
2. Lewmar and Windline are two popular manufacturers.  The Windline BRM-3 https://windline.com/index.php?act=viewdetails&mod=125 has an adjustable roller, and might be a good choice.