NO. stiffer helper may mean quieter driving on a bumper concrete highway.
if its more than 225 lbs helper spring then you effectively have 'progressive springs'... probably used for serious aero and not for you or me

YES

NO. droop is *starting point* of the shock (while standing) to full travel (car lifted)
you change the *starting point* by changing spring perch or spring length, then it changes the droop

IMO, Yes. I use the bar as a trim tool to effect how soon the wheel lifts or late the wheel drops. I also run around -3.25 deg of rear camber. Especially with the rear uprights the rear loves more camber. -4.0 front, -3.25 rear.

hmm ok. so weak-ass helper it is? swift has a 0.1kgm spring

how did you achieve that level of rear camber?

Let me caveat this all with, there are other ways to skin this cat. Ive tried all but high front/low rear rates. Nothing has been as good for me or as fast, especially in tight stuff.

Max camber on the lower control arm, then more low.

To get more at a higher ride height you'd need an adjustable lower arm. Right now the Megan or Racefab is the only ones Id use, especially with my uprights.

more low and more spring is always the answer :)

You should preface this that you're on very wide slicks and (I'm guessing) most often on concrete. Street tires and asphalt will not require as much camber.

The ER endurance Evo with IIRC 220 tw tires running on asphalt tracks also run this much. They have hundreds of hours on track now and just based on tire wear they also ended up where I found in AX was needed.

Yup. Something that ends up very thin when fully compressed. Mine (20Nmm/114lbs) compresses to 35mm which is a lot of 'useless spacer'

I'd be curious to hear what they're running for springs and bars. I may be off on this but my hipshot guess is they're on softer springs/bars than other guys and they're using more camber to account for the increased body roll they get from that. Concrete has a higher coefficient of friction than asphalt, which means more grip, so it's expected for more camber to be needed on concrete.

FWIW none of the regular-ish track evos I've worked with have had a need for more than -2.5° in the rear.

They are running moderate rates. Nothing crazy but not soft either. One other component, a stock upright evo has a higher camber gain in the rear but also a higher rate of change of camber gain (camber acceleration?). With the SSB rear uprights its reset closer to OEM and more linear gain which is the component that makes the rear more predictable. But because of that it tends to need more camber than a stock upright car.

For example, Stock evo rear lowered 1.5" will be in the 1.0-1.1 (off the top of my head) deg/inch and with my uprights goes back to 0.6-0.7 deg/in and a stock ride height evo is 0.5 deg/in.

EDIT: Just to add, this all comes back to making the rear do more work. I put as much load into the outside rear tire as I can which means its getting more roll also. Just make sure rear tires are warm before you go too ham on track ;)

Some tighter/faster (track) corners are banked, which might be a factor

Spot on. Extra droop travel (with helper springs) isn't all that helpful for motorsports situations.

It could help very marginally for daily driving. If you're going over uneven surfaces like a driveway entrance and you find yourself lifting a tire, some extra droop travel could reduce the thunk when that tire hits the ground again. But that's about it.

Unless you're jumping the car, in which case you're going to need a lot more droop travel. :D

one way to find out is to put a 4x4 block of wood under one rear tire, & see how much the other side droops. I'm on 'soft setting' only on the rear sway bar and I could try it later

Dallas

Is ER running your suspension all around?

When you say moderately stiff, do you mean 12kg front 14kg rear, or substantially more spring rate?