Before I put in my two cents, a word of caution: any defoliation of an autoflower comes with a bigger risk than defoliation (trimming) for photoperiods. This is because they will transition into the flowering stage based on age as opposed to light schedule so you have a very limited time in which they can recover from the stress of defoliation. This means that if they don't fully recover from the stress before they start automatically flowering, they may be stunted and yields may be reduced. With photoperiods, you can keep them in veg for as long as you want/need for recovery before switching to a flowering light cycle of 12/12. (all of which you probably already know, but putting it here for the good of any newbies that might not know.)
Now to answer: If you're going to train autos, it sounds like they're at the right size AS LONG AS they are vigorous and healthy. If they show any signs of stress, aren't growing vigorously with a beautiful color or the environment isn't perfectly dialed in, any topping or defoliating is not recommended. You refer to the bottom leaves. Are you referring to the very first round leaves (the cotyledons) or the first 'real' leaves? And what is the thought of removing the lower leaves? In training, you would remove the top node or two so that you break the apical dominance and get multiple 'top' colas and the plant grows in more of a tabletop manner instead of its natural pine tree shape. Removing bottom leaves won't help that at all.
The time you would want to remove lower leaves is if they're spent towards the end of the growing cycle, if they're not getting light, or if you're purposely defoliating to send energy to buds, etc. If the lower leaves are still getting light and they aren't yellowed/wilted there's really no reason to remove them. Even those original rounded leaves are fine to leave as they usually dry up and fall off on their own.
And not sure why you wouldn't want too many bud sites since more bud sites = higher yield (disclaimer: to a point) but that requires more time to recover in the veg stage which with autos you don't have. That's why, generally, topping isn't recommended for autoflowers. HOWEVER! Nebula wrote a f**king awesome article about training autoflowers:
https://www.growweedeasy.com/how-to-train-autoflowering-cannabis-strain and she walks you through everything in perfect detail. Give that a read and you'll have a pretty good grasp on training autos along with the risks and potential benefits from doing it.
Lastly, any training that you do should definitely be low stress so that your plant has time to recover during the limited time in veg that it has. Unless you're feeling like taking a calculated risk and you're okay with a potentially stunted plant or lower yields, stick with just bending the plant over to one side and tying it down along with the secondary branches to help form a tabletop shape. If you feel like being wild, try topping it below the 4th or 5th node in conjunction with bending/tying since that combines some more aggressive training (topping) along with less stressful training (bending/tying).
Keep us posted with what you do and how it goes! Looking forward to the updates and good luck!
