Just don't break any branches and you should be alright. Causing harm to the plant while flowering slows the process and I don't think its really worth it. However if you tie them down you should be ok.
I personally tie down, bend over, LST, or what have you as much as I can to get as much light to my girls while flowering. I wouldn't recommend topping them or anything, but tie them down all you want!
Basically pinch a branch to soften the tissue inside the stem but not crush it, Start to slowly bend over, any resistance pinch a little more, then weight said branch down, it will heal it self at the "bend" and those nodes on that branch receive the same amount of light as the top of the branch - lots of buds
Google search on the topic wouldn't hurt either
Tried to do search forums for "supercropping and super cropping" there's a TON of pages here also
i would say lst would be better just because supercropping stresses your plant some and you dont want any stress (or as little as possible) during flowering. the more stress you have the smaller your yield will be in the long run. if you LST you will see great results even if you are just starting flowering.