Note that 'actuator' refers to any method of movement, whether it's linear actuators, motors, servos, musclewire, etc. It looks like you are talking about linear actuators.
The second diagram nicely conveys what your setup would be. To calculate the forces the linear actuators will exert, you will need to calculate the torques that your 'Load' exerts at pivots 1 and 2. However, to do that, you will need to specify the lengths of the linear actuators, and determine at what angles you're calculating the load at. It should be reasonably straight forward to set up a series of equations which you plug in lengths/angles/positions to, and get the loads on the linear actuators at various positions.