The time lag argument for idealism As I have to go away for a few hours, I will continue.
I take it to be a conceptual truth that if event d occurs at time t1 then it is present at t1. If you think an event d can occur at t1, yet not be present until later, then I just think that's a contradiction. When an event occurs is when it is present and when it is present is when it occurs. "It's occuring now, but is it present?" makes no sense.
So, the event d occurs - and so is present at - time t1. That is, d is 'now' at t1. Not after, not before. But at t1. It has presentness at t1. These are just different ways of saying the same thing.
If my sensation of d's presentness does not occur until time t2, then d appears present when it is not. That is, my sensation of d's presentness is false. If materialism is true, then all my impressions of presentness are false. Nothing that I sense to be present is actually present. The event of my sensation of d's presentness will occur after d is present, not simultaneous with it. And that's true of all of my sensations of presentness if materialism is true. So they're all false if materialism is true. Which is why it isn't.
If I understand you correctly - and I am not at all sure I do - then all you are saying is that my sensation of the presentness of d will be present when it, the sensation, is present. Which is true, but beside the point. For the sensation of d's presentness is of d's presentness, not the sensation of d's presentness. And d is not present, it is past.