Hello Ig (nice shortened form btw), and welcome to Tapastic!
In your case, I'd recommend setting the episodes/pages with the examples you mention and similar stuff as NSFW (there is an option to do it when you're uploading the page). I don't really think that there are 'limits', but if you want to be sure, you can include an additional warning at the beginning of the comic, this time without setting it to NSFW, so that everyone who starts reading the comic sees the warning and understands it before keeping on reading.
I suggest this because 'NSFW' can be a bit ambiguous sometimes. I was accustomed to it meaning 'this contains sexual stuff you may not want to see in a public place', but many people use it for extreme violence too and not just sex. If you set it all to NSFW, some people may be turned off thinking that the comic is too sexual rather than gory.
That said, I'm looking forward to reading it!