MadDog, I considered using U-bolts, as it wouldn't have required a lot of drilling; in fact, that's how I'd fastened the plastic milk crate base to my
B2150 ROPS. However, I rejected that approach this time for two reasons:
a. It would have required a projecting extension to the upper crossbar, which would have caused hang-up problems; as in, the shoulder of my coats, and the choke chains when going in and out of the basket; and
b. There would more likely be a tendency for the heavily-laden basket to slide down on the FOPS verticals, possibly interfering with the extension of the top-n-tilt ram. I neglected to mention above that one of the positioning criteria for the basket was that it allow full range of motion for that top ram when using any of the implements. Finally, I wrapped all the tnt hydraulic hoses with some twist-on plastic protector stuff ("Rhino Wrap") that seems really tough; got it from the local logger hydraulic shop.
Note: I had also considered drilling & tapping the FOPS verticals, but the metal wasn't thick enough to provide enough threads to securely hold the weight of the basket without stripping out. So I ended-up drilling all the way through the FOPS, back to front, and using carriage bolts with nylon locknuts.
PS: I was born & brought-up in "Winchestah" MA. Left there in '57 and haven't been back since. Military service, gummint service, etc.