There was a ui mod on the eqinterfaces forums that had this, but the problem I've found is that the server tic is bugged a few ways -
1) It doesnt last 6 seconds. It's a fraction of a second under. Over the course of 8 minutes you'll lose about a second.
2) Your hp / mp regen won't change just on the tic. Probably because of #1, it happens in 2 or sometimes 3 steps over the tic. Just speculating, but I think it's changing for "Yourlast known HP + your expected regen" on the tic, then a few seconds later it changes to correct that based on whether you were sitting for the exact turn point of that tic. That turn point does not always match up with when you get the tic increase; if you don't find that sweet spot, you'll end up seeing an increase followed a second or two later a decrease in hp/mp from jumping up and down at the wrong times.
And occasionally there is a third up/down in hp/mp. I still dont know why the third change sometimes happens.
Trying to use an in game timer mod was a serious pain in the ass with all this, so instead of using a ui mod I ended up using a metronome when I really need to maximize. It's easy to resync a few times an hour when the server tic gets noticeably off.
Free Android app -
http://mobilemetronome.gabrielsimoes.tk/