I am not familiar with NT dosing - I just shared what I've learned from research (including reading many, many books about hypothyroidism)
I would think you could increase by 1/4 grain more but, definitely get labs before any more dose changes....you certainly don't want to "overshoot" your goal.
Re dosing times - I am aware of most people taking NT that space their doses MUCH closer together. As in, first dose in the morning and the second dose 6-8 hours later.
I do believe you'd want to space your dose so that it is 1-2 hours before/after a meal and definitely 4 hours away from calcium/iron (these interfere with the absorption of the T4 component of NT)
I take my Cytomel (T3) med at 8AM and 2PM - since T3 is so fast-acting, split dosing helps prevent hyper symptoms after the dose and keeps me going throughout the day.
I'm surprised that 5PM dosing time hasn't caused you any difficulties with falling asleep at night (unless you're a real night owl