How long would it take to complete all of the old Relic weapons?

[Terin]

You will leveling faster than you will get relics weapons finished. It still takes at least a few months. If I can risk an advice, if it is mostly for glamour, just do it when you are in mood to do so without really thinking about the time it takes.

This said, you can do one in a few weeks if you are really dedicated. What will slow down you the most is if you don't have enough tomes (though you can solve it with roulettes, Eureka and hunts).

You can use it as glamour as soon as you don't destroy it. About the copies you can buy, I'm not sure how it works. For Eureka, I know the last step needs BA to be down.

Well, my main is already 80 (although his PLD job is only 60), so not too concerned with leveling. Mostly just experiencing the story of that, and getting some cool Glamours along the way!

To be honest, I've been capped on tomes for like... over a year, lol. Is there anything I can be buying in advance?

As yeah, it would also be nice to know the state of Glamouring the "copies" or whatever. I would ASSUME that you can get all of the stages once you finish the chain, but would definitely be great for someone who knows to confirm that.

Also... in terms of the "head-start" for completing the previous Relic, how much of a head-start are we talking? Would it be better for me to try and work on all the Relics simultaneously, if I'm going to be waiting on weekly lockouts/timers? Or am I just as well doing the ARR Relic, then Heavensward, then Stormblood, and then Shadowbringers?

[Eldevern]

Also... in terms of the "head-start" for completing the previous Relic, how much of a head-start are we talking? Would it be better for me to try and work on all the Relics simultaneously, if I'm going to be waiting on weekly lockouts/timers? Or am I just as well doing the ARR Relic, then Heavensward, then Stormblood, and then Shadowbringers?

There are probably items you can buy in advance. Just check Relics steps to know what you will need. The annoying part is the books steps. You can buy them only one by one.

You can do the relic of each extension simultanously, they are not connected.

There is only one things that can't be done in the same time : a relic phase.
You can do ARR relic 1 phase B and ARR relic 2 phase A but not two phase A.

[TaleraRistain]

Would it be better for me to try and work on all the Relics simultaneously, if I'm going to be waiting on weekly lockouts/timers? Or am I just as well doing the ARR Relic, then Heavensward, then Stormblood, and then Shadowbringers?

I've been working on 9 HW animas for newly minted 80s I have along with up to their Recollection version on ShB and noticed some overlap.

First set of memories in ShB can be gotten in HW FATEs. This is also the place to get crystals for the HW anima first step. You can also turn in your finished ARR relic to skip this step but it's not hard to get a crystal from each zone if you don't want to.

Bitter memories you can get from either 50/60/70 or Leveling Roulette (I forget which one). There's two quests in Idyllshire where you run 50/60/70 Roulette and Leveling Roulette to get Singing Clusters.

There's a quest in Mor Donuts to run the three CT raids for aether oil and there's a drop from the ShB weapon that can be gotten here, I believe.

Stormblood has no overlap. It's entirely in Eureka. ARR I haven't done in ages but I don't think it has a lot of overlap, either.

You are going to need a lot of poetics and GC seals or you'll want to be a crafter/make friends with one. There are some steps like HW Umbrite which is only poetics and you need a lot, so I'd recommend using any alternative routes on items as much as possible. Some of the old crafted items you can get with GC seals so Greed on all that stuff, lol!

https://ffxiv.consolegameswiki.com/ has great guides and they do a good job on each quest of outlining the needed items and how to get them, so you can stockpile for a future step while you're working on an earlier step.

[Fland]

ARR I haven't done in ages but I don't think it has a lot of overlap, either.

You can get Nexus light in CT raids. So you can do the 3 CT raids for aether oil quest (HW relic) while also getting Nexus light (ARR relic) and memories (ShB relic).