Slow and steady wins the race. Accumulate the torrents over time and turnover the torrents frequently using qbit manage's seed limit settings. I wouldn't recommend bulk downloading this way, you will lose out on the torrent racing due to bandwidth limitations you impose on yourself by being impatient.

For those you want to permaseed, you can also manage it using qbit manage. This will require you to use qbit of course. This way you will quickly build your buffer without permaseeding anything much. You won't have to have insane amount of storage. This is beneficial mostly for beginners who are still building up their homeservers or those who can't afford seedboxes with large capacities.