Whopity
I have no doubt you are correct but I think you are asking the tyro pilot to run before they can walk, I did The IMC rating with the sort of hours that you talk of to start the IR.
To tell the truth I dont think I could have taken the IR & multi engine all in with so little flying time to back it up, The IMC was the hardest thing I have ever done in aviation (apart from the A320 ground engineers CRS course) and to take that to another level and chuck in the multi engine as well is likely to be too much for most tyro pilots.
As for your pricing I should think that people should be paying IRO £100/hour for a 40 hour block.