The rose joint spacers (if done proper) should go part way into the rose joint, so a bit of machining may be necessary.
We have them in stock in stainless steel made specifically for our sized rose joints.
Ours are offset spacers done like that to keep the original factory castor settings. Some makes of adjustable TCA's will push forward the castor by a small amount if the r/j spacers are central.
The cranked and straight arms make no difference, if you draw a line from the centre of the ball joint top it should be straight right through to the centre of the rose joint.