The info you've got on lowering a beetle rear end is equally true for raising it, just turn the torsion bars the other way.
As you've got the coil-overs its even easier, as these will flatten out any minor discrepancies you make in the turning operation.

Hurrah!
After a long hiatus with rebuilding the engine, my Mk1 GP Trials Buggy is back in action.

The Buggy Spec is like this....
Engine Type 4 103mm x 74mm giving 2466cc
CU heads with 44x38 Valves, Engle 110 Cam, Manton rods, 911 Tappets
CB Ultra Fuel Injection and Electronic Advance system.
Dry Sump lubrication allowing 8Litres oil capacity
153bhp
Link Pin front Axle, IRS Rear, Std front Brakes, 63 Transporter Rear Brakes
Hydraulic Handbrake
091 Gearbox with custom First & Second gears, T2 CV's
Notched spring plates (T3 double plates) for extra ground clearance. 1303 torsion bars - nice and soft.
Raised shock absorber mounts
165x15 Vredestein Sprint+ on the front, usually run at abut 7psi
185x15 Matador MP300 on the rear, usually run at 15-18psi
Fuel tank is a galvanised Mexican item with a Pre67 filler neck bolted where the sender would normally be.

For the uninitiated, trials are the art of driving up steep muddy hills without getting stuck.  Points are lost according to where you stop NOT how fast you go.
Cars must be road legal and satisfy a number of MSA rules, the most significant one being NO OFF ROAD TYRES
Trials are a relatively cheap form of motorsport, get you out in the winter all over the country and let you use your buggy for what it was designed for.  Trials are slow enough to be safe, but fast enough to be exciting.
If you thought they were dull, look at this shot.....
 

Check that your windscreen is firmly bolted and braced.
The vibration at the mirror could well be the windscreen itself having a bit of a wobble. (as they say..)

My Buggy comes out of hibernation in September and goes back in in May.
Reason - Trials!
Motorsport for buggies (and others) in the winter months.
http://www.youtube.com/watch?v=ksZsuwFVroE