Well if its of any use, I turned the letterbox back on and set it at about .. erm ...0.057500 so its behind my UI still and not visible , I had a big performance boost (ie hardly any lag in towns) but also after re-locating the bags the stayed put !!! ... like I said elsewhere some things seem to snap in relation to where the top / bottom of the letterbox is if enabled or where its default location is if it is not.....
I know this may not make a lot of sense, but play with the letterbox and the position of the bags and you should see what I mean......
