For the electrolysis part of your question, time to completion depends on several variables such as:
Speed of the electrologist, speed in turn is related to what epilator and mode of electrolysis is used, how often and how long you are willing to go in and lay on the table in order to reach a full clearance, how well you tolerate the sensation, how well you budgeted for the several months it will take you to get full clearance. For large areas with a lot of hair, you need a strong commitment to stay on an aggressive schedule according to YOUR particular hair removal condition. Time varies with how much hair you have, in other words. For areas like you have, you need to go with a MODERNLY equipped electrologist who can go fast. That means, MicroFlash or better yet, PicoFlash thermolysis, with the automatic timer set well below one second. Any electrologist already doing this knows what I’m talking about. Appointments should be 2 hours or more in the beginning.
This is not an easy task for either party, but IT WORKS and you will have permanent hair removal. Check out poster ‘bryce’ and read his thread.
One of my clients who had his back hair removed from upper arms, shoulder, neckline to beltline received his first, full clearance in 7 months. He came to me for two hours a weeks. After that, we maintained the whole back, shoulders and upper arm areas for another 7 months. Cost was around $4,500. You can negotiate for buying packages to get a price break.
So this is not cheap or easy, but it does work as long as the electrologist has the right set up and stamina.
Not sure I understand your first question about the size of the follicle? The main thing to know is that the coarser, denser and darker the hair (and lighter the skin), the better response one gets when a good laser is used by a skilled laser specialist.