Installing subframe connectors

I am going to use larger bolts to attach the rear of the connector to the frame. Going from 7/16" to 1/2". The holes in the connectors are already drilled for 1/2", don't know why they send 7/16" bolts. Will also fabricate some crush sleeves to put in the frame, to keep the frame sides from collapsing. I'm using 3/8 pipe, which has an ID of 1/2 inch, and fits the bolt snugly. OD of pipe is 11/16". Here are some pics of the pipe for the crush sleeve on the left, with the 1/2" bolt in the center. Smaller 7/16 bolt is on the right.