Don't be confused by the long, over-explained instructions. Give them the EXACT size you want tip to tip. Ignore the fabric size qualifications identifying how the fabric will be smaller by 7/8 to 1 3/8". NOTE: Blindster is NOT the manufacturer. They are just an online retailer/middleman. The blinds come from a manufacturer in Florida.
Response from Blindster
I'm sorry you had a problem with our instructions. Roller shades are our trickiest product for measuring.
I can't agree with your statement to ignore the fabric deductions. You have to take into consideration the tip to tip measurement (at the top which is the widest part of the roller shade) because you need room to mount the shades on an outside mount and you have to make sure they will go inside the window opening for an inside mount.
The fabric deduction is important as well. With an outside mount you want to make sure that the fabric covers the window. For an inside mount, we are just making sure that you know there will be larger gaps (larger than any other window covering) on the side of the shade when compared to other blinds/shades.
There are very few (if any) retailers of window coverings on the internet (or via other channels like big box stores, distributors, etc.) that actually make their own blinds/shades.
Thank you for your review.