A few solutions:
Hydraulic Torque wrench: Something like a Hytorq or Aztech. You can control the torque with the hydraulic pressure.
The World's Most Trusted Industrial Torque and Tension Systems - HYTORC
You could go mechanical with a torque multiplying wrench, but it sounds like you will not have the ability to use one.
Final idea is drilled bolts with bolt heaters. There are usually use on things like Steam Turbines with huge bolts. You "stretch" the bolts by inserting an electric bolt heater into a drilled cavity. The bolt elongate a set amount, based on the temperature. You then lightly snug the nuts and turn off the heaters. The bolts contract, giving you the amount of tension needed.