I believe most clients allow you to limit the upload rate so I would set that to something that is less than your max upload rate so that it almost never causes an issue. The limit of torrents it more limited by your network and what your computer can handle.

Usually that isn't a limiting factor so it's not something you have to worry about. You can technically leave everything unlimited except for Global Connections and Upload/Download bandwidth, those are really where you'd want to set limits if necessary. Your torrent client is capable of auto managing everything else.

(network wise) it isn't about number of active torrents but the amount of active connections you have in total, which is very dependent on your router, isp, vpn. but usually if they aren't shit, and especially on a private tracker you'll run into other bottlenecks like bandwidth, io, or whatever

It depends, but the weakest link will likely be whatever is performing NAT.

For private trackers Im happy if many torrents are active. Just limit download speed a bit so you dont nuke your normal browsing

I'm not an expert, but I've had hundreds of torrents seeding and never had a problem.

Concurrent active torrents? So you mean only the ones that has activity on them? Entirely depends on your system. If you have ssds, you can have a lot, with hdds, not so much. I would limit the upload slots per torrent to 3-5 and set the global upload slots to 75 or something like that. Looking at the statistics of the io time in queue can also help. I have about 19k torrents and 30-60 are active out of them on hdds. Once on EMP freeleech it hit 100+ active ones, that was when I limited it as that was too much.

I'm currently seeding like 50+ torrents across 2 different private trackers. Have each torrent limited to like 500 connections and I forget what my global is ATM. Only time I ever ran into issues was Hogwarts from a public tracker which was able to saturate my network. Upload like a tb in a week then got an email from my ISP and called that good. Got a 10 ratio on a public tracker which is probably better than 99% of people who use them 😂

Just run things and find out. It really depends on your network and environment. Take note when things act up or slow down and scale back.

I usually have over 1,100 torrents seeding but maybe a dozen or so are active at a time. Maybe more sometimes, I don't watch it as closely as I used to.

A few times I've added hundreds of movies at once by importing IMDb lists and experienced network errors. I had to download them in batches.

So far I've only run into this with public torrents. Most of the time all my private torrents see little to no traffic. Its probably not the best idea to try and seed everything on the front page of a tracker, but older torrents which would have to be searched for are probably cool to just seed 24/7 without them competing over each other.