I have seen that type at hardware stores, you can cut with a scissors to fit.   

My mother will be living there and running the store, and I would be the Landlord and partner to the business. 

Write it down, get it notarized for 5 bucks at a UPS store.

BiggerPockets is getting ready to release the 2nd Editions of their Flipping Houses and Estimating Rehab Costs books...you'll find that between these books, many of your questions will be answered:http://www.biggerpockets.com/store

We often do Sears Outlet.The big box stores, Lowes/HD. 

Also look into midtown around the Sears store.

After reading a bunch of blogs, posts, watching videos, googling, I ran across the book "How to Invest in Real Estate" (https://www.biggerpockets.com/store/how-to-invest-in-real-estate-ultimate) and decided to buy it and read through it in a few days (reading it again). 

on file, the building is classify as 8 units(2 stores on ground floor and 6 apartments on top). there is an attic with high enough ceilings and i would like to convert the attic into two apartments or maybe one apartment. 

There are (8) yes, EIGHT grocery stores in Mandarin with a 5 mile path.

Strip malls, retail stores?