Its a good job the cheque book is not involved.
Your wish list seemed quite Doooable at first till the small brain kicked in.
There was enough input / out put pins, but not enough of the right sort for
your wish list.
Two generated load inputs and two house load inputs.
and my 0 to 5 volt proportional out put, Pulse width modulation
output, serial out put, L.e.d. Bar graph output.
A redesign with multiplexed data lines and digital to analogue out put was called for.
There is a blue link on the board. Installed means eight stepped outputs proportional to available power above house load.
With the blue link removed output is a 0 to 5 volt signal for driving an Industry standard thyristor controller with out put proportional to available power above house load.
A five volt pulse width modulation out put is available for both options.
http://steamboilers.homecall.co.uk/PCB4.jpgSoftware still under test but seems to work
Regards
Alan