My current Diveney is very similar in design, my 3rd Diveney BTW and I'm convinced they were all the best playing cues over the past 30 years I've been playing with tens of cues.
Put the cue on the rail of the table, with the joint touching the rail and the butt on the table and the shaft hanging over the table. Roll the cue and see how much wobbly wobble there is at the cue tip. You're welcome.