on tack eyelets vs. d-rings...
The fact is that a 4-roller pulley; 8-to-1 downhaul system is necessary to easily apply the downhaul tensions that are a part of correct rigging.

The Loft places stainless steel eyelets at the tack and we recommend the purchase of a 4-roller metal pulley hook.

This system has the advantages of downhaul ease, and is actually one step better than integrated pulleys as the windsurfer does not have to thread the downhaul rope for each rigging.

I see the 8:1 metal hook/eyelet system as the best solution for downhaul ease and efficiency.