Decide the fixing position of the blind, within the recess or outside the recess.
Do not deduct from your sizes. We deduct 10mm from the width if specified inside the recess.
If fixing outside recess we recommend an overall overlap of 75mm on the width and drop.
State all sizes to the nearest millimeter, measure recess width and drop in several places, always give narrowest measurements.
Always measure using a steel tape measure and check for any obstructions in the fitting area.