how to create a more specific D365 sales pipeline

Dear all,

I would like to forecast the sales pipeline more specific than just on opportunity level.
Our opportunities consist of bulks of hours of our different consultancy expertises.
Would it be possible to create a chart which reflects the hours to come for the different expertises?

My thought was to try and use the Product Line Items for this, with write in Products
but i dont know how to get these write in products visible in a (forecasting) chart
Does anyone have any tips? ARe Product Line Items the right direction or should i try to accomplish differently?

Many thanks in advance for the replies
Best regards, Leo