I'm trying to figure out what size openings I should tune my oar locks to. Should the oars be able to slip through the horn opening with relative ease, should it be fairly hard to pull them through, or should it be nearly impossible without great force? I currently have Cataract SGG oars that are 1 7/8" outside diameter. My oar locks are from Recretec and have a horn opening of 1 5/8" which is the same as all of the NRS oar locks. Should it be that tight of a fit or should I open the horn wider? I'm assuming I shouldn't have to take my oar blades off just to take the oars out of the locks. Right? Any advise would be much appreciated. Cheers!