After a couple of weeks of thought, some calls to various other builders the bottom skins were riveted on without a helper. There seemed less chance of catching the latest lurgy when not working face to face with a helper. Hermits tend to work better without helpers. The bottom skins came out brilliantly, all the holes fitted perfectly and no lurgy was caught, Vans is really quite outstanding; though the downside is that this is a slow process.
Although a camera was used to start with, once the confidence was established the camera was disgarded.
The process is as follows: 1. Rivet all along the bottom 2. Rivet the vertical rivets starting on the two middle ribs and work outboard and upwards as per the top skin. 3. Use jigs which ensured all rivets heads were accurate. 4. Sit back and enjoy the inspector being miffed at not finding a slovenly rivet.
The telescopic helped to gain comfidence at the start but was disused after a short time.