I do have an Explanar in the studio and find that apart from the 12 o'clock position (where the Explanar fins are located), its very hard for the uneducated eye to spot an off-plane shaft.
The weighted roller club may be resting on the circular rails, but it may not be conforming to 1-L-#5, "The clubshaft lies full length on a flat tilted plane."
The best plane board undoubtedly is the one that Homer recommends - a rectangular plane with a circle in the centre - per 7-7, "Always view the Plane as rectangular (with four ninety degree corners)...", which the pictures in the book depict.
Agreed on all points, Justin.
Life is a compromise.
And it is also short (and thus requires a competent Golf Instructor).