i'm also in the market making business for our USD, BTC, and SILVER markets and so i'm viewing these ideas from that perspective.
#1 we have a natural supply limit to any smartcoin, which is some function of excess BTS people are willing to lock up in collateral for that particular smartcoin. there's also an upper bound based purely on exchange rate and amount of BTS required per unit of that smartcoin. 1 million bitUSD is far too large a number. we're probably looking at more like 100,000 bitUSD at current BTS valuation and amount people are willing to tie up in collateral.
#2 juicy spreads are what induce liquidity providers to enter markets. in absence of any support/intervention, simply observing spreads shows us what kind of risk/reward market makers imply for our assets. artificially narrowing this spread (albeit by fixing settlement ranges and thereby reducing some risk) could easily induce market makers to leave the DEX.
that said, i am in support of some upper and lower range for settlement, as suggested by
@JonnyBitcoin in other threads. the range would be something like 20% for starters, though, not 2%. further, everything we try ought to be on a limited experimental basis for a single smartcoin. derive measurable hypotheses, test over a limited range, then advance policies that are proven (conditionally) to work. never stop experimenting...