Pin Box Adjustment Question

[C130]

I'd like to get some opinions on adjusting a Trailair Rota-Flex pin box, trailer on a Grand Designs Momentum. I know it's not a Keystone but a pin box is a pin box in my opinion but know there's lots of smart people on this forum. There are only two height adjustments and it was at the lowest position. I need more spacing between the bed rails, currently between 5 1/2-6", closer to 5 1/2, as my bed cover isn't flat along the bed rails. Just going through my storage unit facility I have to be careful because there are large storm drains that cause a significant amount of roll and I get with about an inch of hitting. My Hensley TS3 hitch is as high as I can get it and still close my bed cover. I'm sitting a little low (2"-3") in the front also but it tows great and I've had no issues other than not being comfortable wit the spacing.

So, I researched the Grand Designs forum and found some others with the same issue. I can't find anyone that's swapped out their pin boxes and I was willing to try a different one but didn't want to go out and buy a new one without knowing it would fix my issue. I found one guy that moved his pin box down one notch and four out of the five bolts fit. He then drilled a hole to make the 5th bolt fit therefore having the same number of bolts holding the pin box in place. I couldn't find any other options so I did the same yesterday. The guy sent me photos and has towed numerous times with no issues. He had two mechanical engineers in his family look at it before doing it and both said it would be fine. Any opinions or anyone see any issues? I'm not asking for approval or anyone to tell me it's perfectly okay to justify me doing it, just want honest opinions from people who have more knowledge in this area. The only issue I see is there is less of the pin box between the frame it's mounted to but I still have the same number of bolts holding it in place. I can easily add another bolt on each side also. If it's a stupid idea feel free to tell me that also. I can post photos later if that helps.

I really like the Rota-Flex with the TS3 and it's the best tow experience I've ever had but the Rota-Flex is a weird design in my opinion. I'm really surprised it doesn't have more slots for adjustment and it goes almost straight out, hardly any downward angle at all to give it any height. Looked at the Mor/Ryde online but can't really tell if it would solve my issue, need to see one in person. Pin box is rated for 21,000 pounds.