OK. So you have 3/8" centers.
My guess is Lowe's Utilitech GTB-408-UT is a private-label (or whatever you call it) and close cousin to the big supplier Gardner Bender GTB-408 strip which has 9/16" centers.
You'd think these jumpers to make a bus'd connection would be clearly listed as an accessory or companion part to the terminal blocks themselves!
And NYC Subway's barrier strip is yet another option with 7.5mm centers.
And Garrett asks for as the "simplest way".
Anyway, my suggestion to Garrett is to just measure what you have. If you want to use the jumper-strip method to distribute your voltage, then be sure to get one with the correct center-to-center dimension. Unfortunately you may need to hunt or go mail-order around as it appears Lowe's, Home Depot, and the other usual suspects may not stock them...