Hi, I am looking fo opinions on bolting a metal piece   around a 90 degree corner tight. Would you angle 8mm bolts at 1-degree to achieve a tight clamping fit or not do that at all in metal(like in woodwork)-?

1-Piece nr-1 is a backplate 90 degrees that fit into two toolhoders on one toolpost, a very sturdy base I want to use for more than one purpose.

2-Piece nr-2: This is the round 105mm base for my MT4-Borig head inside a bush to it can be turned for ball cutting. I already made this all to fit with handle, great control of 180 degree movement.
Now I must secure this tight at the right height on centre to lathe spindle. To achieve this I milled a big square out of the round base material, this now match the 90 degree corner of the back plate. I want to use 4x 8mm bolts from the top, & 4x 8mm bolts from the inside below on the backplate and angle those at 1-degree to pull it in secure to backplate every time its fitted.

Note:The 105mm round piece is bulky, because I dont have a 4-Jaw chuck to clamp a smaller square, so a lot of it will be milled off eventually after I decided on the final shape of it.