Well you're definitely moving in the right direction.Get yourself a little notebook and make notes of what cars did what,how they handled,tires gears body dimensions and times etc.
Now as far s how they handled,the best thing I can think of is for you to take a look at Alpha's website. It's a little old but the important part is in the beginning and that will help you better figure out what the car is doing.But ignore the narrowing part,that pertains to the older style full width tires we used to run.The important part is being able to tell how its coming off the track so you can address those issues .
Depending on how bad you tweaked it,if you dont have a jig,a good tech block,graph paper and a small square will help you straighten it up.
I'd straighten it up,get a Z28 or foxtail winged up in .004's in roughly the same dimensions and see what it does.Just be sure to take the Viper,this way if the track is slower you can run the same combo and compare thing ;-)
link to Alpha's tech page
https://alphaslotrac.../alphatech.html