Going against some grain .......
I am a Dental Technician by trade and have been for about 40 years. So, I sit and do close work all day and then as a hobby tie flies which is also close work. I found that having my vise high is where it's most comfortable. My lab benches are high as is my tying bench at 23" high. I have had back problems as long as I can recall, even before getting into the trade. about fifteen years ago I got some fully adjustable chairs with adjustable arm rests. Now, I can tie or work with my elbows supported most of the time which takes a huge amount of the stress off my upper back.
I will tie most of the time with the hook just below chin level and sometimes almost eye level. I also find that adjusting the chair height or slant periodically will help eliminate discomfort when sitting a long time.
When you are looking down, you stress your neck and upper back muscles much more than when you keep your head and back straight. Just because a Tyer doesn't feel discomfort when he/she is younger does not mean that damage to the back and neck isn't occurring and that later in life, the trouble will increase. Unfortunately, I found this out late in life.