A lot of engineering is doing things in the right order, but sometimes you don't know the right order until it's too late. Yesterday I took off the cheeseplates with the aim of resetting them in the correct place. A first levelling test this morning revealed than one tower was leaning 14mm to its right, this explains the 14mm skew I experienced when first testing.
I decided to ignore this, and simply shift it 14mm left when using it. The flatness and angle of the top will be set later, so the lean should not matter beyond this. I set it up, but the skew remained. Either the orientation was flat with a sideways drift as I slid forwards, or the orientation was at an angle with no drift. The drift was small, about 30mm, but annoying, there should be none! I fixed it in place, knowing that it's not a serious problem, though a painting that might just fit may slide out of the correct view.
Then I thought it might be the camera, not my stands, and sure enough the so-called 90-degree steel L-plate on the camera was not at 90-degrees. There are adjustment screws on the base and one was loose; the camera was twisted anti-clockwise, which explained everything. If I'd realised this before attaching the cheeseplates I could have fixed it and would have left things.
But the 14mm lean AND this skew problem were too annoying to ignore, and I knew I'd end up starting again from scratch as I've done with countless projects, countless paintings. If it's not right, I must fix or start again. I'm not a perfectionist but I have a low tolerance for imperfections. So, I began to effectively make stand v3.
This afternoon I scraped off the hot-melt glue from the cheeseplates and removed the L-plates from the towers. These were really strongly welded on by the superglue, unexpectedly so. The L-plates are caked in glue and wood fragments, I'd have to dunk them in a lot of paint remover to clean them. At £6 each, it easier to buy more, so I'll do that. The towers are scarred but it's superficial not structural. I'll invert the towers, use the top as the bottom to restart the setting process.
One step is to make a guide, from 18mm MDF, with a 1M guide line and 90-degree flat base in the right place, to place and set the towers exactly vertically. This is now complete.
This two-day job will take a week, but this is part of an iterative design process. Build, expect errors and lessons, rebuild, etc.
