Spring/shock ideal combo need advice

So here’s the scoop.
Need some spring advice, I’ve read a lot about this but recently got a shop recommendation that surprised me.

truck: 2015 DCLB

situation : swapping from icon stage 4 , 2.0 rr all around TO fox 2.5 RR DSC.

concern: current setup had a 13’’ 650# spring (rides pretty good imo)
shop recommends 14’’ / 600lb spring(eibach I believe)

reason I’m confused: I’m about to go UP in weight.
These are the additions;
Aluminum bumper (65-70lbs)
10k winch (80l#)
Ifs steel sliders (54#}
Steel mid sliders(26#)
Slider bars(74#)
LCA plates(24#)

I’ll also be deleting the sway and working the rear end (HH, leafs, shock relocate )

can anyone chime in and help me understand why they’d recommend a drop ?
Will the one inch make that much of a difference in ride quality over going up to 650#?
What should I expect and what has worked for you guys.

thanks in advance!

 

Did you ask the shop concerning their recommendation(s)?

 

I did. The conclusion was based off mathematical equations. I’m not arguing they they’re wrong or it’s a bad choice, just more wondering if anyone else had been in this situation and what the outcome was?

Meaning the effects of the ride overall. What to expect jumping down to 600 but up to a 14’’.
I spoke to someone else at length about it prior to consulting the shop and he swore up and down that a 700# is what I need, no question.

[I understand a portion of this ultimately comes down to personal preference of the type of ride(and how you ride) the truck.]

 

So the 14” spring will give you more lift, then once you add all the weight it will compress being a lighter spring(hopefully ending up at ride height you want) and won’t have as harsh a ride as if you went up in spring weight alone. Looks like they’re trying to find a happy medium imo.

 

Agreed.
So I’m no professional in suspension whatsoever, but my first thought when adding weight would be to at at LEAST maintain the same spring rate and increases spring height in order to compensate for sag...

Has anyone on here gone down in rate and up in length?
If so, care to chime in?