There is a lot of debate on the size of housing of Tokays and bigger is better but honestly you can house 1 in a 20 gallon tall and 2 should be doubled so 40 gallons tall should house 2 with enough room for movement and hiding...etc...(i have housed 2 in a 20 gallon tall and they will live their lives fine but they definitely dont have enough room to move around and is not recommended) but this is only in regard to housing a male and female.
As for 2 males together, this cannot be done unless you want injured/dead tokays they are highly territorial and will fight regardless of cage size.