Default Value in Multiple Data Validation lists based on another cells value

Long story short, sheet1 allows the user to choose what type of service is being performed with a data validation list, there will almost always be multiple line items. Sheet2 then autofills that selection into cell B10:B25 depending on how many services were chosen. Cells C10,H10:N10 then use a vlookup to fill in other criteria (located on sheet3) to assist the user in knowing what material to order, etc. Cells D10,E10,F10 & G10 have data validation lists allowing the user to choose from different materials, vendors, etc. All this was fine and well until the request was made to have the lists populate a default value that is within the list, dependent upon the service located in clmn B, and the defaults change for each of the 20+services that can be chosen on sheet1.

I do have some experience in VBA so definitely willing to use that vs. a formula. I have attached a sample of my spreadsheet, I didn't erase all of the named tables so forgive me if its a little sloppy. I appreciate the help!!

So after much searching I might be able to better describe my issue- I need cascading combo boxes that are dynamic upon each other. Originally I had dynamic validation ists however the older guys at work cant read the small fonts on the data validation lists so I had to superimpose a combo box over the top so they could read it, NOW, anyone have any other ideas??

Your help is much appreciated!!