If you are satisfied with the way your car runs at part throttle, and with the margin of safety you now have, then the s-afc will work good for you. The key is that it basically is good for tuning wide open throttle fuel mixture only. There is no load based tuning option. It does not support timing adjustments either. From what you have said, I would think you would be very happy with it because your goal is good 1/4 mile times (wide open throttle). If you had a wideband a/f ratio kit
you would be able to adjust it yourself. At least you could adjust it for safe wot a/f ratios. Without a wideband, you really, really need to take it to a dyno shop.