[Coley]

Hey Jocko....the rubber hose works great....shows great vacuum readings, etc.
I simply 'tee'd into the hose fittings at the back of the intake manifold where there was a strong vacuum signal. Then ran the rubber hose into the cab. The vacuum gauge had a threaded fitting on the back with a small/short section of steel line so I simply pushed the hose snuggly onto that...no problems.
I can't exactly remember the hose size...but the I.D might have been close to 3/16" maybe? (I'd have to do some more checking to know for sure).
Note: Running a complete hard line is probably not possible due to the flex of the engine when torqueing over. This would be a similar situation that hard oil pressure lines need to respect by having a highly flexible 'winding' area somewhere near the block to limit a fatigue/break point. A rubber hose is certainly the best way to go on this.
All Good
Coley