Hello Bigger Pockets!

I'm in the midst of building a spreadsheet to help me quickly analyze new deals, and the part I'm having the most trouble with is estimating CapEx. My thought is to put together a database of big ticket items (roof, siding, water heater, appliances, etc) that I will update with prices every year or so. My goal is to put in the specifications of the property, like the footprint, and have the spreadsheet pop out needed information, including CapEx.

For example, I'm putting together the roofing section of the database right now and have a wide variety of roof types listed.  Finding the conservative lifespan of each type was relatively easy thanks to https://roofonline.com/.  However, I'm having trouble finding good cost estimates for replacing each type of roof. How much does asphalt single cost to replace (including labor)?  What about clay tile?  Solar panel?  Green roofing?  That's the sort of thing I'm trying to find, preferably cost by square foot so it can be adjusted based on the individual property. 

Does anyone have a good resource they use when looking in a new area (or in my case, starting out in my home area as a new investor)?  Or am I going overboard with the analysis should just pick a number like $300 per month and let future experience teach me if it's a good one?  Thank you very much!