Question - with voltage being such a sensitive factor in the slides, why route the power all the way to the fuse panel and back? Why not a direct run inside the electrical bay to the slide controller? Just pick up via a stand-alone fuse on the output of the solenoid switch. On my 28ss that would be about 3 versus 20+ feet. That would be the same as increasing wire size by two (12 to 8) for a 3% circuit. (I have to presume it is a 3% critical, not 10% non-critical, since it is so sensitive).
May not help as much for the rear slide on 34 (although I do not know where that controller lives), but should help the front slides.
Edit: power goes to the fuse panel in a #6, comes back in a #12, so the improvement is not a full two sizes, maybe one.
2021 Isata 5 28SS with 2020 JLU Rubicon pusher
Prior: 2016 Lance 1995 / Ram 1500 Eco Diesel
2012 Lance 1575 / 2015 Jeep JKU Rubicon