Hey, thanks to everyone who contributed. Learned a little more than before, and now have some new resources I didn't know existed before asking my question.
It became clear, as I suspected, that there is no one correct answer. As with most things "Car", it just......depends.
How much spring is too little, how much is too much......."It depends". Driving style, car setup, course factors....... "It depends".
So, I'll have to find this out for myself. Find "my" answer.
I will be trying the 525# springs in the front this next weekend. That in fact is close to the MINIMUM rate that GC recommends for our cars with their kit. I like the 700# springs on the back, so they stay.
I will report back as to what effect this move has on the car's balance. Fingers crossed.