I definitely won't pull the reinforcement plate... no point in leaving four holes! If anything, I'd grind an oval relief profile into the middle of the bar.
I'd like to find a proper nut... it is just a weird symmetry preference. I know there's a thousand other things I could do to make the boat faster or better-maintained (and I won't even talk about the bearing repack I've been putting off on the trailer for a year). This is the same psychosis that keeps my Buell on its sidestand while I meticulously clean a fairing today that is just gonna get coated in oil tomorrow (Harley motors don't keep oil inside like my Honda motors!)
I used a small crescent wrench to tighten things up for now... I'll scrounge the local Ace stores' surprisingly good stainless sections and/or go McMaster if it comes to that. That said, I am a little tempted by the fella with the anchor bars on ebay for $10.
http://www.ebay.com/itm/161245887986 Functionally, the bar seems a slight upgrade... and substantial overkill.
Randii