I'm attaching CSV files for Fortress and Empire. For Fortress, I calculated "real time" between induction and Maran, or between induction and deletion for people who didn't make Maran. I also calculated "hours played per day" while a squire.

For Empire it's not possible to get "character hours" for each promotion, so I couldn't compute the number of game hours between Oath and Elite. I did, however, compute "real time" between Oath and Elite. I didn't bother to consider people who never made Elite.

Here's the summary:

Days spent as a Squire for those who eventually made Maran:

Min: 5.6 (Kernagor)
Median 15.1
Max: 58.9 (Angaarn)

If you throw out Angaarn, the next highest was surprisingly Iltanthal, who spent 30.5 days as a squire averaging 3.4 hours/day. After him comes Llondolis, who spent 21.2 days as a squire averaging 4.6 hours/day. Both those characters were leaders.

Side note on Kernagor: dude played 14.1 hours/day over that 5.6 day period. That's insane. Tanith wasn't far behind. If you throw out those two, then a couple of people (Enrai and Quiltell) did it in 9 days while logging a "reasonable" number of hours per day.

So I'd say a realistic range for a character that's playing a normal number of hours per day is around 9 to 21 days as a squire.

Days spent between Oath and Elite for those who eventually made Elite:

Min: 3.4 (Eleia)
Median: 20.5
Max: 69.0 (Sarouv)

Here it should be noted that Sarouv is not necessarily an outlier. After him are Carintsei (63.2), Chirikaw (57.7), Rikkiri (56.2) and Clissa (45.7).

The next shortest after Eleia were Klurak (9.4), Opoj (9.7) and Zridv (12.9). Notably, Kostyan spent 21.1 days and Eoria 31.4.

Based on this, 10 days is a reasonable lower limit on "Oath to Elite", but it could take up to ~30 days even if you're performing at Eoria-like levels.

Attachment #1, (txt file)
Attachment #2, (txt file)