Doing 0.25u is really tough because the lines on the syringe are so close together. It's more important that you do it consistently than being 100% accurate because it's just not possible to know exactly where the quarter dose is on the syringe. The markings on the syringes don't help because the lines can be way off on some syringes. The one way to really finesse dosing is to use calipers. If you are interested in doing that, I'll find the instructions. I used them and it does make things easier once you do the preliminary work. You need digital calipers with a locking mechanism and they should be available at Cdn Tire, Lowes, Home Depot, Home Hardware etc.
I can't tell from the pic exactly where you were drawing to but if you were between the first long line and the first short line in the left side lines, you were in the right vicinity.