I know quite a few people needing the low tiers. I myself haven't done much of it and only have the ki from the puk nm sandy t1. It is really just scheduling problem for my little group of people atm. One thing I wonder is if you need all the clears to participate in higher tiers, or can you just hop into any tier fight?
Only the popper needs the clears to pop the NM. If you have a voidstone you can participate, will get cruor/exp/items, you just won't get credit towards stratum progress.