>> If you want to test whether coaching matters, hire a non-fielding coach at FC. Do not try this if you have any prospects at all in your system... glove ratings will plummet. <<
In the very early days of HBD, I did test poor fielding coaches. Based on that, I think HBD hooked up FC and gave them a ridiculous amount of power.
There as a lot of forum outrage back in the day as this was discovered because many worlds had very few 80+ FC. People were paying over 4-5MM for fielding coaches. HDB started creating more that started off in the 70s. Seemed to solve the issue and outrage.
For all other coaching, playing time seems to have such a bigger impact that coaching. So much better coaching doesn't seem to matter much, if at all.
This I've tested. Move good prospects to levels with better coaches. Leave one prospect with a bad coaching, move the other to a level with a better one. Been doing this for many seasons in different worlds. Outside of ML Fielding Coach, I don't see it making a lot of difference.
Yet, here I am asking about how to hire better than total crap coaches for 2 MinL roles. I've never hired a HiA PC with 15 pitch rating and put my #1 pitching prospect there. I have had HiA PC from 50-70+. Can't say that mattered.