I was supplied these stainless steel bracket from the workshops of one of Australia’s defence forces. I won’t say which one, but it has something to do with boats 
The brackets came undrilled, but were supplied with fitting instructions as to hole size and spacing. As they are constructed from 3mm (maybe a bit thicker) s/s plate, there was no need for longer fork clamp bolts. The existing bolts still had plenty of threads inserted into the triple clamp casting. Installation was a breeze. Even the mechanically inept Moto could probably even master it.
The pricipal behind this style of tie down point is that by lowering the point at which the straps attach to the bike, it increase the angle of attatchment. This more obtuse angle provides more stability, and less chance for the bike to sway sideways. The issues of the bars being damaged by chaffing of the tie-down hooks is also eliminated.
Having said all that, I haven’t actually tried mine in the real world yet. They could actually be a load of crap and end up failing and flipping my bike off the trailer and hitting a crowd of disabled nuns on the footpath 😆
Here are some pics for your perusal.


