i would not want to top an auto unless i knew for a fact that the strain can handle it, if you top to get more thats great but some autos do not respond very well to topping and you lose out on a bigger harvest, if i was you i would do some lst, and tie down those branches starting around the 4th week from seed, you start at this stage 4 weeks from seed as most autos will have room to tie things down, and between the 4-6 week mark is when some autos start to stretch around 5 week mark, so if you start at 4 weeks from seed and keep working the l s t you should be able to open up the flower sites for maximum light exposure.
so again if you have never grown that auto strain before personally then like i said either grow one out with out doing anything just so you can see and learn how that auto grows, or you could do 2 seeds one you LST and the other you just let be, so you can compare the two.
so if you want max. yield, then a few things would help, a bigger pot and of course more light on the flower sites that will become those big fat juicy buds we all want.
so only do LST to start. topping is fun and i speak from experience about topping an auto and losing out on a big harvest because the auto didnt like to be topped. so
live and learn and i try to pass that on to other growers so they will not make the same mistake