I want to create a list of ""types of work"" and apply a percentage to each

No Problem.

here is a way to ensure 100% and save on data entry effort.

Make the first two fields be regular data entry numeric fields like you probably have now.

But for the last field change the field type to be a formula numeric field with a formula of

1 - [design] - [production]

Perfect!!!!    If you would be so kind - now I want to pull a report (pie chart) that is broken down by the values I just created.  Design, production etc. What I am trying to end up with is that with all of our projects - this percent was design, this percent production, etc.

You will not be able to easily create a Pie chart due to the format of your data, with each record needing to be in multiple slices of the pie.

But fear not.

I suggest a simple Summary Report.

Summarize each of those three fields, respectively using "Averages".

I suggest to group by month or quarter.

Start with that report to see if it meets your needs.