Snippet of the code:

I copy from B, paste into A.

Set A = Workbooks("SwbA").Worksheets("SwsA").Range("A1:A10")
Set B = Workbooks("twbB").Worksheets("twsB").Range("G1:G10")
A.value = B.value

I want to be able to declare a variable such as

Dim col AS STRING
col = "A" 

So I can do something to this effect -

Set A = Workbooks("SwbA").Worksheets("SwsA").Range(col&1:col10)

Please take note, I don't want to do this -

col = "A1:A10" '--> this works, for other reasons I want to manipulate Column letter only

Please help

I can't see your image but you can do

 Dim Col As String
 Col = "A"
 Dim r As Range
 Set r = Range(Col & "1:" & Col & "10")

Column Issue

When you declare a column as variant you can use either the Letter or Number. The Cells property is then appropriate to use.

Number of Rows

Sub NumberOfRows()

 Const cW1 As String = "twbB" ' Source Sheet or Book
 Const cW2 As String = "SwbA" ' Target Sheet or Book

 Const cCol1 As Variant = "G" ' Source Column Letter/Number
 Const cCol2 As Variant = "A" ' Target Column Letter/Number
 Const cFirst As Long = 1 ' First Row
 Const cLast As Long = 10 ' Number of Rows

 Dim rngB As Range ' Source Range
 Dim rngA As Range ' Target Range

 Set rngB = Workbooks(cW1).Worksheets(cW1).Cells(cFirst, cCol1).Resize(cLast)
 Set rngA = Workbooks(cW2).Worksheets(cW2).Cells(cFirst, cCol2).Resize(cLast)

 rngA.Value = rngB.Value

End Sub

Last Row

Sub LastRow()

 Const cW1 As String = "twbB" ' Source Sheet or Book
 Const cW2 As String = "SwbA" ' Target Sheet or Book

 Const cCol1 As Variant = "G" ' Source Column Letter/Number
 Const cCol2 As Variant = "A" ' Target Column Letter/Number
 Const cFirst As Long = 1 ' First Row
 Const cLast As Long = 10 ' Last Row

 Dim rngB As Range ' Source Range
 Dim rngA As Range ' Target Range

 Set rngB = Workbooks(cW1).Worksheets(cW1).Range(Cells(cFirst, cCol1), Cells(cFirst, cCol1))
 Set rngA = Workbooks(cW2).Worksheets(cW2).Range(Cells(cFirst, cCol2), Cells(cFirst, cCol2))

 rngA.Value = rngB.Value

End Sub