.25U adjustments takes a little practice, but are very doable. Do you have syringes with half-unit markings? They make .25U dosing much easier. The main thing you want is to be consistent. Some folks set up a syringe with water and food coloring to use as a guide.
I see you are following SLGS. Have you read the stickies at the top of the forum? Both the SLGS and TR stickies are packed with tons of great info about when and how to adjust dose. For the most part, we do adjustments in .25U increments here for a couple reasons: because it's the best way to find the ideal dose; and for safety.
Let us know if you have any further questions!