Pittsextra:
I think you are not wasting your time following the Viscount route.
I remember reading that the plan was to price the first 1-11s the same as the last Viscounts. The latter was said to be (but not verified by me) £800000. I can try to find the quote. That would give you a 55 year old price point for prices in pounds Sterling.
You said you're looking to check profitability. Using list prices will obviously overstate profits by such an enormous margin as to make any result meaningless.
Just in case you're not aware, Airbus and Boeing do post current sticker prices on their websites.