You don't mention whether this is for a DS1 or DS2.
I had a piece of SS channel cut and drilled by a shop. This allowed me to drill sideways for the through bolts. Their location ended up just barely inside the trunk, but the CB never touches them when raised.

(On a DS2, you may have to contend with the liner being separate from the actual trunk.)
The CB is a bit lower than the fairleads, so you will need to angle the cleats. Either by providing an angled seat, or using the wedges that cleat manufacturers supply for this purpose.