Idk if it's just me, but RM seems to use aloooot of processing power.. ram too.
So if you plan on using RM, i'd say 16-32gb ram, preferably 8+ core CPU (Intel all the way, get the newest you can)..
ohh, and water cooling

running basic fans is gonna be a pain in the ass with more than 3 pcs.
and you might aswell up it to 60 bots, and then do a 3 pc setup, using a 3 split since you only want to run the bots 10 hours a day.. up it to 12 hours, and run 2 "groups" a day A/B to cover all 24 hours for that maximum efficiency ^^
so do;
1) 20 - 10/10 - 12 hours each
2) 20 - 10/10 - 12 hours each
3) 20 - 10/10 - 12 hours each
A good base to start is:
MSI gaming pro motherboard with SOCKET 2066 ( but isn't cheap )
or msi x299 raider motherboard SOCKET 2066 ( cheaper )
msi geforce gtx 1070 8gb
feeding 750 watt
kingston hyperX 32gb DDR4 or higher depends on you
Extreme intel core i7 7740x
( and a case )
cooler for your processor and a toothpaste ( im not sure the name of it in english, to keep the processor socket cool. )
i think that whould be a nice way to start and work higher on...