I wouldn't do much on the small plant, if any. Branches at cotys tend to be weak. There's so little beyond that you probably don't want to cut anything off.
A lot of this depends on knowing how much growth you'll get after flip. you'll have 4 weeks of strong vege growth remaining ( = stem elongation / new leaf). Some people get different growth rates than others in addition to all the genetically caused variety out of our hands.
Growth that you can predict will be buried deeply and end up being shitty larfy buds is a prime candidate for pruning. You may want to let them grow naturally a few cycles and so you can more accurate guess at these things.
i'd suggest doing something systematc. e.g. this time prune up to top 3 nodes. Maybe you'll find you should wait a week into flower to prunen to "X nodes" etc.. If you are systematic about it, you can adjust and learn a proper procedure faster.
It's always a bit of a guess. You never know when you'll have that 3x growth or 2x growth after flip for certain. Breeder info can help but it's nowhere near 100% accurate.
It might be better to let them grow naturally this time ... if an area gets crowded you can always prune off whispy/weak branching near bottom later on. Learn how much vertical growth to expect. See how much variety there is in this regard. Some people do there last wave of pruning 2 weeks into flower. When you do it can help mitigate genetic differences in your canopy... same with training.. some plants are better off trained horizontally for an extended time compared to other plants in order to maintain a level canopy.
Can easily prune off the excess if you have a goal for your final canopy, too. I shoot for 2.5-3 colas per sq ft.. i'm not worried about fractional differences too much. But if i know how many vertical colas i want, it makes for a much more efficient plant getting there... and easier to know what is growth i won't use and can be pruned off before it wastes more resources/energy.
I'd say grow it naturally, continue to some training to spread the plant out as it goes -- it'll always fight to bunch back up. Maybe take off some whispy shit after a couple weeks of flower to de-clutter lower area. the small one can't have much 'waste' on it to prune off. The concern here will be maintaining a level canopy. Maybe use a pot elevator (anything that raises it off the ground to level things out)
in the end and only considering common sense contexts -- DLI = yield. How you train mostly just impacts how that bud mass is distributed. obviously, if you prune off a bunch of branches it can hurt yield in many cases, too. You're not going to circumvent 50-70g/sq ft through training, defoliation or lollipopping. Heck 'from-seed' grows may not even his 50g/sq ft due to some portions of plants being low-yielding phenotypes or maybe you have to remove a hermie etc. 70g/sq foot would require clones of a heavy yielder. (supplemental co2 can go higher)