Depends on the ratio. The 2/3 effect still plays a part, but if you beat that ratio and have lvl 2 sos then sh makes more. I believe.
A true SH (SoS being level ONE) makes way more than GH. Bc of mechs, you lose plunder when upgrading. Hence why staying SH is so popular
I believe they said you can only have one at a time for each. But then they gave 2 chests for winners of a broken war despite whatever you had. Some people had a stack of 3. After that Im not 100% sure if they continued to allow it to stack or if it was a one-time thing. So, to my knowledge, they do not stack and you can have one of each
If you really need colors... There's a bbcode guide in offtopic. Look there. But default color makes you seem less stuck up