I actually am going to do a 'mock-up' of the quilt top with fabrics from my stash--the finished size of the piece is only 110 cm (43"), but even when cutting into my fabric, I don't want to 'waste' a whole lot there, either!!
The line I quoted is written:
Alle Masse sind ohne Nahtzugabe (Nahtzugabe 0,75 cm je Seite dazugeben.)
Thanks for your replies!!
I think I am going to plan on adding the 1.5--I can always cut stuff down (on my mock-up one), but it'll be harder to add to it!