Severe Covid-19 restrictions locally have left me out on a limb unable to be side-byside with people who can set me on track for a few things! Hence the bombardment of questions, for which I apologise. But almost there!

The InDesign QC individual (who accepts my ConTeXt-produced pdfs) wants some tweaking to my layout, saying, in simple terms: Odd/right pgs left margin should be 20mm and right margin 15mm; even/left pgs right margin 20mm and left margin 15mm.

I think the difficulty is that what InDesign calls margins might be termed a little differently in ConTeXt and I have no experience with InDesign.

My initial setup was as follows for a paper size defined as [width=140mm,height=216mm] double-sided setup (in other words a standard 8.5"x5.5" book):

\setuplayout

[backspace=16mm,
    topspace=12mm,
    header=6mm,
    headerdistance=10mm,
    footerdistance=9mm,
    footer=8mm,
    width=fit,
    horoffset=12.7mm,
    location=middle,
    height=198mm,
    marking=on]

There was no mention of 'margins' as such in that layout, and the result is close to what is wanted but not quite. Do I solve the problem by adding in: leftmargin=20mm,
rightmargin=15mm,

or is it some other item I need to adjust to ensure the 20mm/15mm dimensions requested?

Julian