There's no such thing as syringes with quarter unit markings....half unit's as good as it gets.
When you're doing doses between, you pretty much have to eyeball it, or you can use calipers. If you use some colored water (coffee, tea, water with food color) with a used syringe, you can play with it and try to figure out where that 1.75 is without risking the loss of any of the insulin
You can also pull up exactly 1 unit (of something other than insulin) and if you slowly twist the plunger, a drop will form at the end of the needle. Try to get the drops to be a consistent size and then count how many drops are in 1 unit...then (for example) if you get 12 drops out of 1 unit, you'd know that if you pull 1 unit of insulin and then "wasted" 3 drops, you'd be at .75
You should have gotten 3/10cc, 30 or 31 gauge, 5/8" U100 syringes...sounds like that's what you've got..holds up to 30 units.
As for the ProZinc syringes, you can donate them if you want to. You could give them to your vet to give to the next person who might need them, or Diabetic Cats in Need is always trying to help members here with things they might not be able to afford.