Move cover page colour and blank coloured end page to doc-specific files. That way output where the colour isn't appropriate, such as Nook or the newly introduced A4Lulu output (which is the A4 book but with white cover page and no end coloured page, and so suitable for using as the content on Lulu, where the cover is separate) can omit the colour.

% Format for a graphic with a single tune
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measurenb false
writefields SRBDZHN 0
titleformat Y0
titlespace 0
topspace 0
infoline false
writehistory false
musiconly true
scale 0.9
botmargin 0pt
leftmargin 0pt
rightmarin 0pt
topmargin 0pt