There are loads of variables here, so there's no 'right answer'. Think about things like:
How are the clients distributed between the client radios? (2.4 / 5 GHz - look at Wireless > RF Spectrum to determine how busy the channels are)
Personally I'm not a fan of blanket disabling 2.4 GHz - many environments are short of channel space. If 2.4 GHz is not over-burdened, in your specific location, then using it gives you more capacity. If it is already really busy then yes, consider disabling it or minimising use of it.
How much traffic are the clients generating? many clients generate very little traffic, much of the time
What applications are they using (particularly demanding ones, like real-time voice/data)
What kind of connection rates are being established? (clients connected at low rates will consume more airtime, to send the same amount of data).