I'd preferred to just use 2 exchanges as it was very manageable. But, this needs to focus and spend more time on the computer.
And in regards to time frame, a shorter time frame is the best, well 5 minutes is enough. But I never recommend this strategy to newbies, that certainly be risky for them as beginners as the use of leverage trading are just for experienced traders and day-traders.
Yes, it was good to use stop-loss for fund protection and avoid big losses. This needs to master as well and must apply in all trading forms.
Using multiple exchanges diversifies your portfolio and your trading very equally. Which means that the risk is lower, sure you may not earn as much but you will be able to not lose too much as well. Sometimes people need to ask themselves, do I want to earn 100% profit with a risk of losing 80%, or do I want to earn 20% with a risk of 5% loss?
I usually end up being in the second group, because I rather have a low losing risk, which in our crypto world is a big ask, because we have even bitcoin dropping significantly as we have seen recently, but it is definitely not a big deal. All in all, we just need to end up being a bit more patient and it will all go right.