In things market, there are not enough coins for sale for bigger deals and Gladimor already said the first deal was an exception for its too small number of coins with slightly above 20k, so anyone new not able or willing to go for 50k or even close to 100k coins will have do with the market in future. Then we as investors could raise the market price somewhat with buy orders as well if we are concerned about it. Then I don't think larger price explosions would help the coin much, it would look good for our investments but could deterrent potential new investors and attract short time pump traders instead. Some steady growth as further payouts are building up trust sounds better to me.
Private sells are all good, if the coin market price is not dipping below ICO levels. There will always be people who dump below their investment price by various reasons, so there should be enough buy pressure to keep the price on ICO level or higher. Private sells currently distract that buying power, and coin price falls. With price falling, new people get in at lower cost, and they will have much less ROI period, so soon they will start dumping the coin further. In any case its not right for the early investors getting worse rates than late ones. The people buying from dumps are those late ones, who get better deal.
Related to ICO investors buying all the dumped coins, well it depends on how much did you invest initially. If you think you invested less than you could, then yes, you would better buy now. As to me I have probably invested more than I should, and am thinking I would have done better if I just picked up from dumps instead of going in at the beginning.
Saying all that, yes 1.5 x ICO minimum sounds good enough. Those of us who invested for dividends, don't want big surges in price, so big private deals at that level are completely ok. The most important part is however - do not undermine buying pressure, so price would not dip too much too.
In any case, I believe Gladimor understands all that, and will choose the right way to go forward.