How do I get Seluvius to sell me ashes?

[Amanozako]

The wiki currently says the trigger is unknown. Here is the order of quest operations I performed:

Offer my allegiance to Ranni.
Talked to everyone in the tower.
Found Seluvius' laboratory.
Spoke to Seluvius--he tells me to give a potion to Nepheli.
I proceeded along Ranni's questline (note during this time I found Seluvius' merchant servant and bought the weathered map at some point, and I talked to Ranni's war general in person outside the tower, though I doubt any of that matters, I mention it here just in case) until I got access to Nokron, explored it a bit to grab myself some crafting material and bailed. I do not have the fingerslayer blade at this time.
Gained access to Altus Plateau.
Completed Dung Eater's questline until I could give him the potion, and did so immediately when offered.
Talk to Seluvius, and he now recognizes I found his secret lab after he talked about the odd result of the potion shenanigans. At this point he offers me a free ash and I take one.

Now, at this point talking to Seluvius only grants me access to his spells. I bought all 4 he had on offer. What am I supposed to do to make him sell me the ashes? Other info I can think of that could matter: I have 4 starlight shards atm, and have 2 great runes (Godrick and Radahn), I do not have the Starlight Amber or whatever it's called, and I DO see Dung Eater's body in Seluvius' basement now.

Please help! I want to finish Ranni's questline but if I proceed further I'm under the impression I'll be locking myself out of Seluvius' remaining stuff.

P.S. this is my first playthrough, and while it's not exactly blind, I'm trying only to look up information about missable content.

[Sir_Noob]

Go collect 5 starlight shards

[Silent Warrior]

You took from him a free Spirit Ash. Equip this one and use it somewhere, to fight some enemies. I go usually to Gatekeep Ruins, but you can do it at any place.
After that go back to Seluvis. There should be a dialogue option now, that you want another spirit ash. If he still doesn't offer the other ashes,then you need to travel a bit around. Rest at some graces, visit his secret cellar once more, reload the area....after some of this actions his shop should get triggered.
Btw: It's not necessary to buy his spells, in case you want do it again with another char...
I buy from him the Dung Eater ashes with every of my chars, and after using his first offered free spirit ashes it worked always this way. ( You'll need one more Starlight Shard for him)

But idk if it matters when you didn't pick up the Amber Starlight, when in doubt, you can give it to him, just to make him happy.

[Amanozako]

He hasn't even asked for the Amber Starlight yet. Is it normal for him to just not mention it until you have it?

[Silent Warrior]

Originally posted by Amanozako:

He hasn't even asked for the Amber Starlight yet. Is it normal for him to just not mention it until you have it?

Ah, I think I remember now. He asks for it only after you have bought another spirit ashes. It's been a while since I played it, so maybe I forgot the right order. But I'm very sure about using the first spirit ashes you got for free, and then reload 1 or 2 times the area to trigger the new dialogue.

[Amanozako]

I was finally able to advance his dialogue to get the puppet purchase section. I both went from 4 to 6 shards and summoned the ash puppet he gave me once before I tried talking to him again, so the solution is probably one of those two.