Scipioanswered grow question a year ago It is possible to Top autoflowering plants. However i would only recommend that experienced growers attempt to Top autoflowering. And even then only with strains they are familiar with and have grown a few times. Topping stresses the plant and can result in a slowing of growth. In Photoperiod plants this is usually not a big problem as you can allow the plant as much time as it needs to recover from the stress. But autoflowers start flowering after about 4 weeks. Meaning the plant can lose up to a week of that growth time. Which can result in a reduced harvest.
It can be done, but it is more difficult to get the result you would hope for.
Personally i fine Low Stress Training to be very effective and less risky. i combine wire tie downs and a trellis net to achieve similar results.