The big problem with having become a pro tyer is I never buy just a package of anything. I have so much fly tying material that it takes up one complete long wall, floor-to-truss bottoms in my garage. I buy things in dozen, thousand, pound, half-dozen, etc. size of a single item. I don't even know the total value of my inventory of tuing material other than it is more than some small shops have as their stock.
I have been holding my scissors in my hand since the second year I was tying flies and that was way back in 1962 when I was 9 years old. I learned how to tie from Herter's PROFESSIONAL FLY TYING, SPINNER, AND TACKLE MAKING book and in it he mentioned that a pro tyer by the name of Leon Wronski of Pennsylvania tied with his scissors held in his hand by looping a finger loop over his ring finger and holding the closed scissors in his palm. I was tired of having to stop and pick up then put them back down each time I needed to cut something, I decided to try and hold the scissors the way Wronski did.
I cut materials by simply putting my thumb through the thymb loop and operate the scissors with my thumb and ring finger. Scissors with adjustable finger loops work best for holding them in your hand. I use Anvil curved blade standard scissors for my all-purpose scissors because I found they are among the best scissors on the market, the and they have adjustable finger loops.
Also, the Anvil standard scissors have long enough blades that the blade barely sticks out above your hand when being held in your palm. This is important so that you don't stick yourself with the scissors when holding them while tying. And the curved blades are more versatile than the straight blade ones because they allow you to trim spun deer hair after it is spun.
Like you John, I tie as many spun deer hair bodies as I need (usually between 2 and 5 dozen) before I trim any of them. And I lay my materials out clockwise for the most part. I do place animal tails on my thigh though because it makes it easier to pick them up and cut the amount I need than having them on the tying table. And I never cement any fly heads until all the flies are tied that I tied in a given tying session. This means that I may have 10 dozen flies to put head cement on at one time. My steelhead and salmon flies (streamers too) always get 2 or 3 coats of medium viscosity head cement because doing so completely fills the voids in the thread and the flies not only look nicer, they last longer as a result.