.276 first try
.222 second try
however your theory is wrong simply because, elo isnt fully reaction time, a part of your elo is your equipment, which affects fram rates and your ping. Simply put someone with .4s reaction time on a 120fps 40ms system will outreact someone with a .2s reaction time and a 30 fps 130ms system.
also elo counts on your knowledge of the game mechanics, for instance last hiting isnt very reaction time base thing, it is more of a routing sort of like dancing. it is highly preplanned, and by experienced player more easily readjusted in case someone goes wrong, like missing one. When i first started if i missed 1 cs in the plan i would miss the next 3-4 now i dont because i can readjust my last hiting pattern really fast