There are two very basic things to consider when looking at matching amps with cabinets - impedance and power handling.
The impedance is articulated as ohms and is a measure of the resistance amplifier will face in delivering power to the speakers (very generally put). The higher the resistance, the higher the ohms. The GK 700-RBII delivers 320 watts to an 8 ohm speaker system while it delivers 480 watts to a 4 ohm speaker system.
Here is the tricky part, putting two cabinets together will change the impedance of the speaker system (making it lower). There is a lot written on this forum about this, so read up on it before you start doing mixing and matching with amps and speakers. In this case, you are looking at what I think are two 8 ohm cabinets (I think GK cabinets are all 8 ohms, but check to be sure). Putting two 8 ohm cabinets together will create a 4 ohm speaker system. So, running a 700-RBII head into one cabinet (8 ohms) will deliver 320 watts to that cabinet and running the same head to both cabinets (4 ohms) will deliver a total of 480 watts to both cabinets. Assume the power will distributed evenly between the cabinets, so each cabinet will get 240 watts at full tilt.
Now for the power handling. Each speaker and cabinet can take only so much power, so the cabinet has to be able to handle what the amp gives it. In this case the both the 410 and the 115 can take 400 watts each, so you can run the 700-RBII at full tilt with either or both cabinets. You'll be OK with wattage. And don't worry, this is very much a professional quality rig.
Note, this all refers to the maximum power of the amp, which you would probably never actually use.