"There should be a setting in your investing platform marked "all or nothing". You will either get the full 500 shares in one shot w/ no partial fills or nothing"
What you say is correct, but I noticed that with EVSI, the market maker does not fill my buy "All Or Nothing" (AON) limit orders even when the limit price is a bit higher than the trading price. On the other hand, If I do not set an AON order but put the limit price a bit higher than the trading price, I often get my whole order filled, albeit in smaller tranches...
My recommendation is to always set the limit price about $0.2 above the trading price, and the chances of the whole order filling is quite high. This is a long-term hold rather than a trading stock, and whether we buy at $5.6 or $6.1 will not make much of a difference in the long run as I believe we will easily double our investment within less than a year...