[aerohead]

Looks good! The unit has a double squirrel-gage. ( twice the fun! )
What I experienced on the BOSCH, was that, as the envelope filled, and the fan was just dead-headed, no longer actually moving a volume of air, and just providing static pressure, the fan power draw fell off, kinda just 'cruising.'
And regardless of the constant electric load on the alternator, the T-100 went over 30-mpg for the 1st time.
Whatever you do, DO NOT use expandable Naugahyde automotive upholstery fabric. The envelope will not maintain its dimensions, wrecking the aerodynamics.
The advertising folks use a Hypalon-impregnated aerospace fabric. Rip-stop Nylon will work, but it needs UV protection. ( it can kill a perfectly good parachute ).