I understand what you mean about the 500 GT. I've never ridden one, but did have the pleasure of riding a Ducati 450 single for a few days while setting it up properly for its owner many years ago.
Yeah, the XZ pulls quite well down low for an oversquare motor and, as I'm sure you know, the piston has less distance to travel than a motor of longer stroke. This has a number of benefits such as less reciprocating mass, less friction (theoretically) and higher possible RPM. It also has drwabacks such as much greater demands from the piston (which does NOT expand evenly across its surfaces) and less 'low-down' grunt.
One of the many outstanding things about the XZ is that it DOES have some pretty good power down low - and then winds out to an excellent (for its day) 10,000RPM factory redline.
Another VERY endearing thing about the motor design and set-up is the throaty, loud and clear intake noise. Superb!
By the way, I noticed in the video you made that you're keeping the motor spinning pretty briskly even when you're not chasing hard acceleration. Just to be ready and on the safe side?
Just had lunch here and it's now time to to thread all cabling and wiring back up to the bars. Clusters, triple clamps, headlight shell, brackets etc etc. have been apart a repaint over the last couple of weeks. Caliper and front wheel too. And most of their nuts, bolts and washers came in for polish or paint while I was at it. Cables all cleaned and oiled and my fuel petcock-to-tank 'o' ring should be ready at the local bearing shop tomorrow morning.
Cheers and happy riding,
Mike