Vet Maelstrom frustrations.... Power-Up Duration Question?

MrTarkanian48

So I spent the last several months grinding dungeons and gear to create a Magicka NB for Vet Maelstrom. Finally got a pretty prime-time setup with all V16 gold gear 2 Nerien'eth w/divines, 5 Julianos w/divines, 3 Arcane Willpower w/Spell damage, Thief Mundus, Torugs Nirnhone Inferno, Torugs Nirnhoned Resto. I have approximately 340 CP (Blue Tree: 28 elfborn, 1 Spell Erosion, 1 Elemental Expert, 83ish in Thaumaturge). My stats are about 40K Magicka, 20K Health, 70% crit. I am on PS4 so I can't see my damage numbers, but I definitely feel like my damage is strong.

Now I go to Vet Maelstrom... I get through rounds stages 1-4 with "relative" ease, maybe 15 deaths. I don't think that is too awful since this is my first time running it on Veteran. Get to round 5 and die literally 100 times on the final boss fight. I'm watching youtube videos for tips, and I know the more I do it the more I am getting the mechanics down, but it is just very challenging for me still. I can get the boss to about 10-15% health, but just always seem to eat some damage before I can finish him off. I am really looking forward to stages 6-9...

I'm really starting to question my self-worth here, lol. I had to stop last night but plan on giving it a go again. I have almost thrown my controller through my TV screen on multiple occasions. I consider myself an above average player, but not elite by any means. My main goal right now is just to complete it, and am not looking for any impressive scores, so I have been using power-ups and have some questions:

1) Does anyone know how long the power-up duration is? Does it last the entire round, or just for a certain amount of time?

2) Can you have multiple power-ups in effect at the same time? Or if I grab one and then another, is the first one cancelled out?

Any insight on these mechanics is much appreciated.