Declaring An Object As A Workbook Is Limiting The Methods I Can Use.

I am trying to compare two workbooks and am running into the problem that since I declared my two workbooks, I am limited in the methods that I can use. Here is all of the code so far.

Option Explicit
Sub UpdateMasterFile()
Dim wbMaster As Workbooks
Dim wbEmailed As Workbooks
Dim wsPC As Worksheet
Dim Master As Long
Dim Emailed As Long
Dim intMaster As Integer
Dim intEmailed As Integer
Set wbMaster = Workbooks("Master Info.xls").Sheets("PlantsCom")
Set wbEmailed = Workbooks("EmailedData.xls").Sheets("NewInfo")
Master = Workbooks("Master Info.xls").Sheets("PlantsCom"). Range("a65536").End(xlUp).Row
Emailed = Workbooks("EmailedData.xls").Sheets("NewInfo").Range("a65536").End(xlUp).Row..............