Hey Juvat, Great job on the 12 second pass! Race cars take patience and a one thing at a time approach. You are doing a great job of doing just that. I would like to mention the front suspension. The front end is more important to a cars ability to hook than the rear suspension. I loose suspension will help a marginal car hook in a car wash. For example, low friction bushings such as poly or heim joints. Low friction ball joints and a good drag shock and spring. Without the ability to transfer weight to the rear of the car via the center of gravity a car will have limited success hooking. I ran a stick car for a few years with a small block and I left on the high chip (shift RPM) and even though it spun a little bit, it made its fastest 60 foots doing that. When launching a stick car something has to give. Either the car accelerates immediately and pulls a big wheel stand or it spins the tires or it slips the clutch. The best way to control that situation is with a slipper clutch. Since you dont have one and they suck on the street, a little tire spin is welcome.
The 2 step is a great tool since you leave the line WOT. Otherwise you have to open the throttle and the motor has to recover from the throttle change. Getting a stick car to work efficiently is difficult, sounds like you are well on your way. Congrats, that 12 second timeslip feels good dont it?!