I am attempting the mage tower and I am looking for some advice. So for my best attempt on Agatha is a 58% pull and I am getting there pretty consistently. I am looking to know what I can improve, gear wise at least, to give me the extra oomph.
Can I still use the Legion outdoors consumables? Should I bite the bullet and do chrome time gearing? I am looking for any possible advice, please and thank you 
Run EN get ravaged seed pod. As for other gear, just run old legion raids for gear with sockets. Gems can make a significant difference. After just practice as it really comes down to how well you handle mechanics. If you have the option, heirloom MoP weps are some of the best to use.
Here is a guide for bis MT timewalking gear. The trinkets and consumables are the most helpful. Just click your class then mage tower at the top 
I hope you get your win!
Am I reading that right in that essences still work?
I don’t think the essences will work in the Mage Tower. But the Heart of Azeroth is a good stat stick item for it.
Essences don’t work in SL but otherwise they still work as far as I know. Except in Mage Tower.
Hmm no, you mean on the heart of azeroth neck? The stats are just strong, essences don’t work in MT.
If you don’t have a buddy to help you get chromie gear (which is overkill anyway) you can also get a crafted dreadful gladiator set, from MoP. They come with sockets and can be made at ilvl 48 which will let you put all the good ole enchants on them that you see in the guide.
Yes you can use Sylvan potion for the 10% stat. It’s pretty OP.
For gear, generally you want to get items that have sockets and are as close to 50 ilvl as you can hit. Some enchants - specifically shoulder enchants - require a maximum ilvl to be placed on. Other pieces just worry about sockets like rings and bracers which you could run class hall bracer and any ring with 1 socket. Trinkets there’s a various amount that are really quite good but I’d imagine seed pod is BiS for agatha because of the AoE. Many people say to do SoO for pieces but they are 45 item level and you do lose a decent amount of stats on those 5 ilvls if every piece is 45 ilvl. Even then i’d only do it for pieces that have 3 sockets. Helmet you just want anything with a meta socket.
No you cant. In Twins you cant use that potion. And if you use it outside when you enter the buff is gone.
Do lower level item scale up? The spreadsheet has me getting a helm from TBC.
From what I understand you queue into the dungeon in chrome time with a lvl44 and they feed you the gear as it will be the ilvl you need it to be.
To be totally fair, Agatha is an exception to this rule. At least, she was back in the day. The reason is because Agatha is technically “outside” on the Broken Shore. It’s why back in Legion, anyone who had Agatha could use the potion which gave them bonus holy damage to demons, which trivialized the Agatha encounter.
Agatha’s zone text is misleading involving this. The Twins are not “outside on the Broken Shore”. Agatha is.
No it won’t. If you go for a Chromie time piece you need a friend with a level 44-45 character to run you through the normal dungeon. That low level char has to loot it and then trade it to you. That is a lot of farming though. I did all my MT’s in crafted dreadful MoP gear, that stuff is close in power to Chromie gear but much easier to get, you might even have the recipes yourself. You can use relics of the past to craft at higher ilvls.
The main thing you want is sockets that you fill with your main stat, the trinkets and the consumables listed. If you use gear that is ilvl 50 or lower you can also use the old enchants listed, which are very powerful in MT. The enchants is another reason to use the crafted gear. Head, chest and boots you will use a relic of the past 5, so the ilvl is above 50. All the other slots you craft with relic 4. That will make them ilvl 48 and you can put the low level enchants on them.