The hotter the better...
I think mine is 1800 to 2500 watts..I paid like $25.00 for it at ACE like 3 years ago and use it daily...
Routing wires is a matter of personal preference once you overcome natural hazards to the bundle..If it's rigid, and safe, HOWEVER you do it is all good...
I sometimes use that same tube you have , But I get it in Chrome...
OR if you REALLY want to make it look good..get one of those Stainless Steel Hose cover kits, like they use on Dress up hoses, (the sleeves aren't really SS..but look like it..)
ON ANY harness I have to run UNDER a car, and especially on 4 wheel drives..I use 1 to 1 ~ 1/2 inch EMT conduit. (Ace, $2.00 for a 10 foot stick)
I bend it to mirror the frame rails and use standard Condulets and Street ELLs for pull and exit.. and use Liquid ~ Tite for exits to like fuel pump, fuel sender, tail and trailer lights..
Liquid~Tite is flexible gray plastic coated conduit mostly for motor make up applications to get the wires from EMT or Rigid Conduit to the motor make up box, and is waterproof..comes in all sizes It Also solves problems on Front clips that open forward and up..the conduit just flexes as it opens and shuts..)
EMT Conduit Also looks "Natural " on roll bars for Driving lamps..provided you bend it to hug the bar.
I mount the conduit with rigid conduit clamps to the frame with Tech screws..
If you do mudding, hit a lot of water and stumps, the wires are safely tucked away in the EMT conduit, not subject to corrosion, rot or being yanked out or shorted..About the only thing you should do is add an 1/8 Weep hole at each end (termination) to allow moisture out..
AND it's super Cheap too..like $20 bucks for all the stuff..
Just a few Ideas..your open to whatever your Imagination can perceive, Provided it's done in a safe workmanship~like manner..(Anti Chafe, rigid mounting,grommets, Stars, locks, AND separation from fuel/heat and rotating parts)