How are skill increases calculated?
Solution 1:
Unfortunately, no one can give you a definitive answer here, because the level up speed of skills depends on several factors
1) How high the skill is, every 15 points (15, 30, 45, 60, 75, 90) the number of skillups increases, see uesp wiki, unknown how big the effect is or if it exists.
2) The position of the skill advancement dagger for your class (between 0.3 and 3.0x)
3) Whether the skill is primary, major, minor or misc for your class (the former levelling faster) (see game manual), unknown how big the effect is or if it exists.
4) The value of the skills governing attribute. E.g. climbings governing attribute is strength. The stronger you are, the faster you can level climbing. (see game manual), unknown how big the effect is or if it exists.
5) The skill itself, each skill follows a different leveling formula (e.g. running is pretty much permanently increased slowly, while the language skills are only checked, when you talk to that creature and failure or success also yield different skill up results)
Testing this is also very hard compared to later TES games
1) Daggerfall is older and far buggier than any modern TES.
2) Daggerfall doesn't display skill exp and you only get skill ups while resting
3) Unlike later TES games, Daggerfall has no mod tools, which allow you to read out the raw values for each skill.
To get those numbers for a later TES merely requires you to read them in the construction kit. To get those numbers in Daggerfall requires meticulous controlled testing with tons of scenarios.
E.g. to find numbers for running, you have to run for one minute, rest, check, whether you get a skill up. If not, reload and run a little longer, if yes, reload and run a little less. Repeat until you find the exact time needed to level up. And repeat this test for different values of speed and running as primary/major/minor/misc skill to determine the influence of those elements.
All those factors make it impossible to give any definitive answer to your question.