pyro,
I'm still new to this, so take it with a grain of salt (no pun intended) . . . I'd still consider adding the cocktail shrimp for a week as it would jump start the cycle. If your LR is like mine, there will be very little die off which wouldn't give much decay to start the cycle. I started a 55 with 45 pounds of LR, 2 cocktail shrimp, and a media that was pretreated with beneficial bacteria. My cycle only took about 2 weeks.
Also, I think it is best to do a water test about once/week to observe the spike in ammonia, then nitrites, then nitrates. If you wait several weeks and your tests come out 0/0/0 your cycle could be done, or maybe it is taking a while to get started and hasn't gotten anywhere.
Again, I'm new, so you might wait to see what those with more experience advise.
Thanks,
Mike