CB setup advice

You'll be better served, distance-wise, by improving the antennas' lengths (but still within resonance) to the maximum that will fit, and if the 70-ohm phasing harness is at all worn, consider running just a single antenna with a new single run of 50-ohm coax. The radio and amp should be wired directly to the battery via sufficiently large conductors to carry the currents required without a significant voltage drop. Remember that the amp won't really do anything for your signal except on transmit, and an old adage maintains that "If you can't hear 'em, you can't work 'em."

So if you've got a little radio budget to fiddle with, first have a shop with an analyzer tell you the state (beyond just the VSWR) of your existing antennas. Then, if you've got enough height above the current antenna tips to still be legal, go for longer CB whips. They'll help with both transmit AND receive.

If your Cascadia is one with a "plastic cab", you'll have to do some foil installation above the headliner (inside of the roof shell) to provide a simulated metal roof for the antennas to work against.

This is all stuff that a fellow with average mechanical skills might do, as long as he/she also had the appropriate specialized drilling, punching, crimping, and measuring equipment and the skills to use them. As a self-professed "pretty new to CB", your first endeavor might be enhanced by going to a commercial shop and either getting them to let you watch them do the work, or pay them to tutor you with the right install and test gear.

Caveat: These are the proper way to do this project from a commercial radio installation standpoint, and follows proven good engineering practices.
Perhaps by coincidence, however, it's also the way hams do it. Accept or reject as you will. Your line about HAM preachers is somewhat indistinct as to what denotes one, and about how much of the info can be rejected out of hand simply because the radio pro is also a ham. That's the case I'm in, although I'm not an ordained minister.
73

 

What handlebar said!

Fix your SWR by getting rid of factory coax, run a single firestik instead.
Run thick wire to radio/amp directly off the batteries.
Take your radio in to good cb shop and have it tuned.

Remember it dose no good to out talk your ears.

 

Oh ... Understood. Some of those folks make all of us look bad

 

I knew what you meant and thought your comparison was humorous! You got good answers to your question. Good luck with your install. Oh yeah, always run your amp on low and it will last a long time, the difference in output between low and hi is insignificant and your amp will live longer if you aren't running it wide open all the time.