IMHO, SLX is too whippy for larger frames/larger heavier riders. In the mid-to-late eighties, many framebuilders put the SLX frame size limit for production bikes at ~58cm; for larger frames they went to a mix of SL and SP (SP down tubes).

The helical reinforcements in SLX and SPX is limited to the butts; the long center sections of the tubes doesn't have the reinforcing. I believe the only Columbus tubeset with the helical reinforcements along the whole length of the tubes is TSX.