Equations, Global Variables, IIF Statements, Linear Hole Patterns & More

I would like to set up an equation(s) to control the overall length and hole pattern of the bracket shown below.

The max length of the bracket is 70"

Hole pattern spacing is 4" from center

***the main problem I'd like help with is figuring out an equation that will ensure there's exactly 2" from the last hole to the bracket edge, even if the global variable "Width" contains a fraction.***

So, if my overall assembly is 58-7/16" (W) how can I set it up to get a bracket that's between 4-6" smaller but whose length is an integer and has the last mounting hole 2" from the edge?

Any help would be much appreciated!

Equations/Global Variables                Value/Equation                                                             Evaluates to

"Width"                                                       = "Width@soXXXXA.sldasm"                                                     80

"D1@Sketch2"                                            = if ( "Width" > 73.99 , "Width" - 10 , "Width" - 4 )                       70

"instance left direction@LPattern3"               = ( "Width" / 4 ) / 2                                                                    10

"instance right direction@LPattern3"             = ( "Width" / 4 ) / 2                                                                    10

"instance to left@LPattern4"                         = int ( "Width" / 4 ) / 2                                                               10

"instance to right@LPattern4"                       = int ( "Width" / 4 ) / 2                                                               10

SolidworksParts And Features