Bracket Spacer needed.. aluminum or steel

[modular93fox]

Hi, Ive seemed to have sourced a place to have the steel brackets made for a good price... however to complete my brake conversion, I need to space the 2 brackets apart for proper caliper/rotor alignment. here is an autocad file (screenshotted) and photo (3d screenshotted) of what it is. Not hard to imagine, but anyway...
Dimensions are 1.00 wide x 4.07" long and as it stands 1.20"thick. If I install the main axle bracket on the inside of the flange, it would be about .25 thinner (ive not yet measured the axle pad thickness.)

The spacers could be 2 pcs to achieve the desired thickeness.. Let me know what you guys think.

The third attachemnt is the assembly of the brackets.

Thanks,
Clint