I've hunted there with several characters, and I believe the best way to powergame that spawn is actually without the parcels, unless your level is too low or you're too unexperienced and can't deal with the amount of creatures, but tbh you can just use energy rings in an emergency situation and ofc use fire protection gear. The only thing I would advice is to keep some parcels on your backpack to use them as a way of not getting trapped, or just build up 'safe spots' with 5 parcels against the wall, leaving an sqm in the middle, so you can run to it and shoot from it after luring if you don't wanna run around, but that's up to you and you would waste less without doing this, just by running them around and shooting waves and runes. In my experience, these creatures move very slow, and they're too widely spread on the spawn to use parcels to keep them on a certain spot, this only works for the tasks, to keep them away of the dwarves, but the way they respawn wouldn't allow you to trap them all with parcels in a certain spot for you to only walk and shoot runes from afar and still powergame. Let me know if you would like for me to show you where the most amount of creatures gather and where do I run them around and kill em. I can take a screenshot of the map and add it to this answer.