I have a sarca and went through this a few years ago.
Got a deal at boat show on anchor and roller.
Sarca roller would not fit on victory bowsprit without significant mods, so sold the roller, and picked up standard standard roller from boating store
I may have chopped the hinge off a hinged one - cant remember.
I then put red poly rollers on o/size bolts for rigidity as it was now a weak sort of open channel. Put the rollers in the spot I needed for the Sarca, and ready to go!
Was cheap and a custom fit, wide enough for the anchor, and self righting ( need to go slow and sometimes a little stop start on the switch to let it flip) and I just let the captive pin swing free. I had intended to drill the anchor for pin placement but honestly doesnt need it . Still use the captive pin when anchored ( rarely)
Have a safety rope on all the time.
Will get some photos for you later in the day.
ps Saw petes setup the other day and looks really schmick!
Cheers
Brendan