I think 6 months is a short time frame. Its better buy, grade and flip but you need to choose the coins because if you grade low the 67 and 68 are more volatile and dificult to sell. If you ncs and ngc is better than ngc only. Im a financial advisor but a newbie in mcc. But i think the good potential is for the long time with roi than 10 x. For example i think in 10 years the 2000 frosted (one example will go for 4000 uss in ngc69) but im speculating. In the short time if you need the cash. If possible you lost a lot of money. For me is a long time investment. And i not sell any of my pandas (69 or 70) 68s is possible i sell if the roi is high. I will sell some pandas when i will buy a apartament. (im very secure the mcc is in the early stage -infancy). But in my oldest years and my daughters will enjoy the fruits.