Nothing better than using copious amounts of grease and the judiciious use of Applied Hammerology for precision adjustments.@border I found a liberal helping of grease on the mating surfaces along with a few wacks from the hammer helped position the crossmember. I did dent the round section, but it had already been damaged offroad in any case.
Apart from which, the grease helps to prevent oxydisation between the laminates of steel once the crossmember has been finally bolted into position.
Pity about the beers, though