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As Rick has mentioned, it is all about total integration time and there is an easy way of explaining this.
Let's say you take 49x60s luminance frames (I pretty much did this a few nights ago with my QHY163M [same as an ASI1600]), this will give 7x the SNR on any given area over a single 60s frame. You really only have 49 minutes of integration though.
If I was using an older noisy camera like the KAF-8300 sensor I would need 600s exposures to get the same amount above the read noise. So 49x600s is just over 8 hours of exposure.
49x60s vs 49x600s, well you don't have to think too hard to figure out which one is going to be better. What you need to consider is that in the fainter areas of your 60s images there are going to be parts that are above the noise floor BUT don't have a lot of signal.
Let's also say that some of the faint nebulosity only emits several photons per minute and only sits JUST above the noise floor. In a single 60s exposure it is going to look like it is just random noise. After 49 images it'll be 7x stronger but noise will still by and far be the dominating factor.
If images are above the noise floor, 10x60s will give more or less the same result as 1x600s. Technically the 10x60s will be a little better but it won't be noticeable at such short integrations.
So, in short, don't worry about the amount of exposures but only the total integration times. Remember, faint things don't emit much because they're faint! In shorter exposures you'll have photons that may NOT show up in every frame so what you need is a bucket load of them to properly sample the frames that do have that faint stuff.
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