Not bad. The toxic flask should probably be your main weapon as it can deal constant damage and will deal knockback. If you should do anything, you should probably play it safe by hanging out at the edge of the pillar zone, and allowing just a few enemies to spawn at a time, eliminate them and go forward a bit to allow a new wave. I'd recommend this be done at the solar pillar because, while it's definitely the hardest, the solar eruption will prove most valuable against the next three.
If you die too much during this process, allow that to happen by creating a small spawn house near where the pillar zone's edge is so you can respawn right next to where you died.
You can tell when the pillar's shield is down by looking at what happens when enemies die. If the pillar is still up then upon an enemy dying a laser-like projectile will go towards the pillar and weaken the shield. The absence of that animation will tell you that you've killed enough enemies. Once that happens, you have no choice but to
#YOLO
Good luck, Nick.