I started having SR regularly before I feel I am ready proceed to pharma/aya, to become more comfortable.

Made tea with 2g SR and some sugar, split with another person in half.

Roughly after 30-40 minutes I started sweating a bit, like cold sweat, but not enough of it to be uncomfortable. Also feeling that "something" is different, but I couldn't put my finger on it. Definitely no OEVs, no CEVs.
These feelings continued for approximately 2-3 hours.
No stomach discomfort or nausea, however eating around 4 hours after Rue administration wasn't the wisest idea: stomach rumbling and gases followed

Now the question: based on description of my symptoms, can somebody advise how to proceed with dosage? I want to achieve threshold dose to see what's harmalas all about.
I was thinking about making 2g equivalent of tea dose this time and then going up/down depending on results.

I started the same way, I like to see how every component and change contributes to the experience.
Your idea of trying 2g next sounds good. You'll see more effects there but likely will not yet be to the dose you use with pharma.
After 2g, 3g, and then 3.5 grams would be good levels as you will probably use either 3 or 3.5 with pharma. Few people seem to really need more than 3.5g.
Once you've reached the dose that produces clear ataxia that is where you've almost certainly consumed enough to have activated DMT, perhaps more than enough. [Ataxia is where you walk like a drunken sailor]
The ataxia and stoning of a full dose of rue tea is caused by the harmaline, that is part of the reason I now refine mine to individual alkaloids. I dont always like the feel of a harmaline dominated experience, but I've never much liked alcohol either.
Its a good idea to keep notes so in the future you can refresh your memory.

If you don't like how Harmaline feels, try mixing some sort of admixture plant with the Rue. 3 to 4 grams of Lemon Balm cleans up how the Rue feels pretty well, makes the Harmaline feel more like Harmine ime, cleans up the body load and headspace, works like a charm.

Ironically I just finished drying a whole pile of lemon balm. Its a good thing I was never able to eradicate it from my garden
I just finished making a new grade of DMT, after I find my standard dose on it I'll be trying lemon balm admixture, as the reports make it sound worth investigating.

Yeah it's a good herb to have around imo/ime, not only cleans up how the Rue/Harmalas feel, but can also help smooth out the DMT come up so it's a bit more user-friendly and not as likely to cause a "bad trip", seems to have worked well for me and others, if you try it let me know how it goes for ya.

There's so many possible admixture plants out there, and they can do many different things when mixed with Rue, Caapi, DMT, mushrooms or anything else really, things seem to work better in synergy/combination. So you can alter/flavor/stylize the Aya/Pharma, and customize it more to your liking, you can clean it up, tone it down or amp it up, add things to it or reduce unwanted side-effects, it's pretty cool, there's a lot you can do with this stuff.

Very informative, thank you!