Hi Susieknitter,
thank-you for your advice and the time you took to type it. I have a Brother KH881 and compatible rib-carriage.
The knitleader booklet's in good condition, and I won't be able to fit the patterns for me onto the sheet, as you anticipated, even using the right or left datum lines.
My cunning idea's to draw a scale with zero on the edge of the vinyl(?) sheet, and do it in a contrasting permanent marker beginning at the top of the sheet, on the glossy reverse side. I clipped across the outer bottom edges to match the real bottom, to fit into the slot. After that, I could xerox the strips of stitch-measure scales onto a suitably tough sheet of paper, and mark the numbers from the edge. Your idea of copying present garments is a good one, and I got some trashed Salvation Army Shop garments in stretch-knits, cut the seams, and used these for patterns, too. Pretty happy today because I have a book of a thousand mix and match patterns for women's sweaters in double-knit (22 sts. x 30 rows / 10cm square) and have got this perfectly on my standard machine with alternate needles on tension 7. Just up to size 34" (86cm bust) but I could graft a strip on either side or knit the garment sideways with a big welt or whatever, such as U-knitting incorporating the ribber, and thereby gain 200 needles in total for this thicker wool. Haven't tried the tension part of the ribber, yet for this idea.
So far, I'm knitting for the little grand-daughters only...