For me personally, Ive chosen not to spend my time trying to calculate the perfect time/price of entry. Instead, Im much more interested in determining whether I want to participate at all (FWIW, I do) by evaluating the project on the basis of the value its attempting to bring to the market and the likelihood of that happening successfully. Based on the outcome of that analysis, I set an allocation to EOS and dollar cost average my way there. I figure that if the project is successful, it wont matter nearly as much (note: Im not saying doesnt matter at all) whether Im in at $0.80 or $1.00 or $1.50.
If you believe that EOS will be a disrupting infrastructure with good potential, then you can invest in it freely. As you say, it doesn't matter if you bought at USD 1.50 and it falls to 0.50. What you are waiting is a 20x-30x gain, so a future price of USD 30 will give you 20 times your investing. It doesn't matter that others that bought at USD 0.50 will have a 6,000 % return on investing. It doesn't matter either if the whole project collapses. You "just" invested USD 1.50 (times the amount you felt comfortable to risk).
It's all reduced to a bet, and you should bet only what equates to the pain of pulling a hair or two out of your head, not to the pain of being hung from your head of hair.