Per the Loki docs, the LSR calculation is:
15000 + (25007/2^((h-101250)/129600))
Where h is the block height.
E.g. using current height 281798:
$ perl -e 'print 15000 + (25007/2**((281798-101250)/129600));'
You can calculate the future LSR by simply increasing the block height.
No you cannot stake more than the maximum amount of 20,000 loki currently as of 2019-OCT-24. The staking requirement gets lowered everyday until it reaches 15,000 loki after 1-2 years. You must stake exactly the required amount of 20,000 loki, if you don't have enough you can open up your staking node as a pool and others can contribute to it to claim a % ...
Given that the staking requirement is a known value, and the number of nodes active on the network is also known, you can calculate the minimum amount of Loki being staked on the network by simply multiplying the staking requirement by the node count. Let's take today for example:
Staking requirement (27137) * node count (465) = 12,618,705 Loki
The process ...