Wiring problems installing new converter

I decided to replace my old Magnetek converter with a new Progressive Dynamics 35A unit. Having some problems with connecting to existing large wiring to my battery. Old unit used two AWG 8 wires for positive and two for negative. They connected to large terminals on the back of the DC fuse board with a large set screw to hold the wires in.

New unit has same type of terminal, with about a 1/4" x 1/4" opening, but at the top of the front of the DC fuse board. Battery wires come in from the bottom of the enclosure and it's very hard to bend them to come up above the board then bend 90 degrees to fit into the terminal.

I decided to get some sort of "set screw" junction box for the AWG 8 wires and a short piece of flexible AWG 6 battery wire to attach to the junction box and to the fuse board. This way my old hands wouldn't have to crimp terminals on AWG 8. I got this.

Problem with it is that the enclosure is only 5" wide and has about 1-3/4" behind the fuse board. Not much room with four AWG 8 wires interfering. Also had planned on 2 junction boxes (positive and negative). The junction box is about 2" X 2" X 1". Don't think I can get 2 into the enclosure.

Found these, but they are too long.

So maybe since I have to crimp to use a terminal board, I might as well use a bolt to hold the 3 ring terminals together. Obviously would have to insulate the positive one. When I installed my 2nd battery, I did some crimping of AWG 8, but I'm older and weaker now. :)

This whole project has been complicated by the fact the unit is at floor level. My old mid 70s body doesn't tolerate me lying down on my side to work on things for more than a few minutes. Another problem is the existing AWG 8 wires only stick out a couple of inches from the fuse board enclosure. Fortunately, this is far enough for crimping.

Any suggestions? Is a bolt for a junction "box" a good idea?

Thanks,