I have seen many ways to make a harness or use terminal blocks to wire these altimeters. I would like to see what equipment you use and how you do it. Please post pictures.
Here are three recents examples posted in other threads, first a Wildman Blackhawk 29 used as a two-stage sustainer. This one just has a common terminal block for the switched positive (high side of the ignitors) and the second lead on the ignitors will be attached directly to the Raven given the space constraints in this bay.
Second is from my Battle Axe build. More room on this board so I put a row of terminal blocks down the side which included two av-bay switches for the alts and then the e-match connections.
And then back of board where Raven is mounted:
Then finally an ADEPT22 in my King Kraken. Here again fairly limited room so I just did a couple of positive common e-match terminals and the second lead of the e-match wires directly into the alt terminal blocks.
Switch on this one is a screw type mounted on the back and accessed through the sampling hole.