Aroma Oil (and a few other questions)

So, I'm making my first batch of homemade ramen (tonkotsu specifically) on Saturday (to eat at night). I'm going to start parts of the process tomorrow night so I'm doing a little final research now and I discovered Aroma Oil.

I've never heard of this till today (but that's not a huge surprise as, again, I've never made ramen at all so). Apparently it helps the broth stick to the ramen and...just makes it all smell even better? But again, the main function is to make the broth stick to the ramen itself.

My question regarding this is;

At what point in the process do I introduce this oil? Do I do it after the noodles are done, in a separate bowl? Or do I do it after I've placed the noodles in the soup itself (after the tare and broth have been added)?

A separate question: I'm trying to do this...as cheaply as possible (not easy and I've been unsuccessful lol). BUT I'm trying to only make one type of tare of which is Shio Tare (salt based).

Can I use this tare to soak ajitama as well? Has anyone done this? From what I can find online, people generally use Shoyu Tare. But I hate bonito flakes so I'm not sure if I'll like that as bonito seems to be the base of that tare. But then again, idk how most ramen places make their ajitama, so it's possible I've definitely had shoyu ajitama and didn't know and loved it.

​

Thanks in advance! Sorry for the long post!

​

Edit: One more question! After letting the tare sit overnight and then finishing the following morning, how do I reheat this once the broth is done? Or should I just make it and let it sit for 10 hours or so while the broth is cooking all day?