I know that there is the danger of having it automatically sell and then it going back up before you can buy in again but I would much rather pay that cost than to be sitting at a 30% loss.
Another risk with stop orders is that if the market gaps way down, way below your limit price, the first trade at that lower price will convert your stop into a market order, and it will be sold at whatever price a buyer is willing to pay you for it.
Stop orders do not guarantee that there will be a willing buyer at your stop price. The next bid could be significantly below your stop price in a fast moving market.
I'm in the US, not Canada, so I will refrain from commenting on your other points.
From a US perspective, even if you get stopped out at your desired price, and get back in later at an acceptable price, there are still potential tax consequences to deal with for getting stopped out, unless you are in a tax-advantaged account.
I want this small investment to grow to be something "extra" for retirement. I will be adding around $750 to the 15k each month.
I think this statement is inconsistent with even contemplating using a stop order. If this is really just "extra," (or even if it isn't) I would definitely put it into a broadly diversified index fund with dividends automatically reinvested, keep adding to it monthly, and just forget about it until you feel like splurging on some extra luxuries at some point in the future.