fishdragon, beware of measuring your old sails to get dimensions. Old sails are stretched out, and the dimensions will exceed the "correct" dimensions for you boat. When in doubt ask the loft if they have the design specs for your boat, or use a steel (not fiberglass) tape measure and also measure the dimensions on your rig. It is an assumption, sometimes wrong, that the correct original rig is on an old boat. When you're ordering sails--you don't want any assumptions.
Also consider that a loft which is paying attention to business should be willing and able to answer any question you have--and if they don't or can't answer, maybe that's a reason to use another loft, even if it costs a bit more.
You may not want racing sails if you are not racing. Consider that a cruiser may have just two sails (main & fore) or four sails (add two storm sails) while a racer is more likely to have 6, 8, 10 or more. A "light main" for winds under 10 knots, a heavier one, multiple foresails, etc. The weight and shape of the main can be cut for specific wind ranges, and you might want to think about your local winds and ask the loft about cloth weight, etc. Durable usually means heavier, and heavier is not so good if you are in an area that has light winds a lot of the time during sailing season. OTOH if you are in a region with constant heavy winds--you don't want a lighter less expensive cloth.
Don't be afraid to ask the loft. Or to tell them, you're new to this, what other options should you be looking at.