Some thoughts:
I don't expect that you'll actually sell out on this IPO.. Yes this thread has exploded lately, but it's not nearly as busy as, say, NEM.. NEM Stakes are also at a current market cap under 1M (when you account for the fact that only ~600 are on the market).
Not saying the level of innovation isn't there, but the question is whether you can expect to see sufficient earlybird adoption to sell out the presale. My guess is that you'll see something closer to 25%-50% of the presale purchased. The end result is that a smaller amount would be premined and the marketcap would thus be much lower, leaving more room for growth. The size of the presale is also somewhat concerning.
How long before the amount of syscoin doubles? Well, a premine of 18% is 360 Million coins. Based on block timing and halving schedule, it would take 2 years before an amount equal to the premine is mined. TBH, not sure if that's a good thing or a bad thing, but it does seem like quite a long time.
I lightly invested. We'll see what happens
