My original thought was simply to bungee the board with the gauges to the handlebars somehow, so that I'd be able to see what was happening with the throttle open under load. But when I tried it I immediately saw that the handlebar mount for my GPS gizmo was crying out to be used. A trip to Ace hardware secured a 1-1/4-inch swivel-ball with a 1/4-20 tapped hole and a handful of 1/4-20 hardware, all for about $3 (i wish they'd had a 1-inch ball, the size the mount uses on the other end, but no joy). It works great...
...although I'm not sure how well I'll be able to see the tach on the road, but at least the ball-swivel gives a decent range of adjusument so I'm sure it'll work OK, which I intend to find out as soon as it warms up and the roads melt some <g>. Oh--for those wondering what meds I need to ride my /6, the prescription bottle snugged in under the clutch cable holds my earplugs where I'll have a fighting chance to spot it and remember to put them in before riding off (I'm pretty protective of my hearing).