Detailed character creation and Twilight/Warping

In detailed character creation, which seems the one to which all the older magi from all books in the line more or less adhere, a magus gets 30xp/year to spend as the player likes, minus 10xp/season of labwork (to a minimum of 0 xp).
Note that this is not the "very" detailed character creation system in which you actually know which sources the magus is gaining xp from, what kind of labs/aura/resources he has etc. It's just the step immediately more complex then the "template based" one.

We also know that a magus can be assumed to gain an "average" of two warping points/year; and indeed, older magi we see in supplements have warping scores. So far so good; if I make a magus who's 30 years out of gauntlet, he gets 60 warping points and a warping score of 4(10).

But magi we see in the supplements also have Twilight scars and Virtues/Flaws gained by Twilight. What is a reasonable system to do that? What is the system that the folks who designed those characters adopted (did they just eyeball it, ...?).

For the two magi I did for Magi of Hermes I just added a few things that seemed to fit stylistically.

Are you able to reveal the system you used for advancing characters in Magi of Hermes? What general presumptions were within the scope of the project?

We just used the rules from the core book for advancing characters after apprenticeship (30 xp or levels of spells per year).
There were some things that had to be specified

We decided that seasons to teach an apprentice did not have to break up complete years of study and cost 10 xp per year, the 15 seasons of instruction could be taken as a lump.

We did not give characters exposure xp for their time in the lab.

Some of the characters just received 30 levels of spells per year as described in the advancement rules while others used the option to take time out of their study and use the lab rules. As a result, some pf the characters have a bit richer selection of spells than others. You can look at the activities in the last 15 years section to see this. I'll note that early in the character's career taking 30 levels pf spells per year restricted to the spell acquisition guidelines in the character creation chapter allows for the selection of spells that would be very difficult for the character to research themselves at that point in their career so their is, at younger ages, less of a power discrepancy than you might expect (and aside from Gwidion and Scipio the characters didn't really get too old).