I have spring recomendations on my web page. A lot depends on what kind of ride you want and what size tires and horsepower you have.
Mooky, Welcome to the forum.
It turns out the drop spindles cause some problems with tie rod to tire clearance, and lack of accepting larger brake upgrades.
Plus, while they maintain the stock geometry, the stock geometry is not good for handling.
Lowering a Camaro by using shorter springs puts the camber curve in a better place than using a drop spindle.
Also a drop spindle is heavier and cast iron not forged steel like the stock spindle.
The Camaro has bump steer problems which can be corrected by heating and bending the stock steering arm. You should not try to heat and bend the cast-on arms of the drop spindle.
I've also heard reports of caliper hitting the upper A frame, and the wheel rim hitting the upper ball joint or upper A frame.
Use the search link, upper right of this page to read the past messages on the subject.
Check my web page for First Gen Camaro suspension info:
David's Motorsports page
First Gen Suspension Page
67 RS 327 Origonal owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer