^^^ Ding ding ding on comfort/ ride quality being affected by shock tuning, especially the high-speed damping. I'm sure Brandon mentioned the same thing.
Also, it's a bit technical and pedantic, but there's a difference between a helper spring and a tender spring. You describe a helper spring above-- completely compressed at normal ride height, and used to maintain load on the main spring at full travel. Helper springs have practically no spring rate-- maybe 10 lbs/in.
Tender springs have a higher spring rate (150 lbs/ in, for example) and are used to, essentially, create a progressive overall spring rate. The tender spring is not fully compressed at normal load, but will close at a given load so you're only using the main spring. That said, both springs may compress at the same time so it's not like you only use one spring (tender or main) at a time.
As for corner balancing, I believe a few places in the Twin Cities can do it-- not sure how much they'll charge though. I believe Jeff the Alignment Guy does, I'm fairly sure Imola Motorsports (
www.ImolaMotorsports.com) does, and I believe Auto Edge (
www.auto-edge.com) does as well. To fully take advantage of it though, you should have at least one adjustable swaybar endlink in front and rear so any preload can be removed from the bars. Since changing ride height side-to-side may twist the swaybars, creating pre-load, even just one adjustable endlink will allow you to get the sides of the swaybar parallel again, removing preload.
While you'll have a tougher time determining side-to-side balance and crossweight on your own, you can use ride height to adjust the front-rear weight balance and therefore handling characteristics. As a general rule, lowering the rear ride height will dial out oversteer by shifting more weight onto the rear tires, raising the rear will increase oversteer by removing weight from the rear tires. This obviously takes testing and tuning though.
Finally, the site below has some good calculators to play with but you need to know so many very technical inputs that I've used it more for theory than for actual planning and tuning.
http://www.racingaspirations.com/app...ion-calculator
Finally finally, I know you have done events and are not a noob, but I have to continually preach for driver mods.
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