Roller Furling Luff Foam

[Sailorman Ed]

Looking at buying a used roller furling genny but will need to add foam luff tape. Sailrite has it but at $2.75 per foot. Where is a more economical source for this? How much of the luff gets the foam to improve the sail shape when partially furled?

[Sonosailor]

My jib has more layers of foam as you get closer to the belly of the sail. I would suggest it may improve sail shape for partially furled conditions, but also improves the lay on the furler so that the sail wrinkles less and possibly lasts longer.