Backcrossing back to auto is where everyone goes wrong, you do not backcross to the negative traits of the AF parent. You back cross to the non AF parent and inbreed to regain the autoflower trait! Backcrossing is thus used to gain even more of the photoperiods genetics you wish to adopt, and autoflowering genes will be brought out through breeding. The process is speedy in comparison to other breeding projects because the autoflowering genetics are easily recognized simply by growing out large numbers of seeds under a 18/6 light schedule , and wait for those plants that show sex. Use those to breed a new generation, and so on. 
