I recently pruned my chilli plants after watching some videos on topping.
I was more aggressive on plants where there were signs of new growth further down the stem. In other places, I left some side branches.
After seeing some overwintering videos, how aggressive can I be with pruning in the spring? I'd essentially like to keep the plants, but for some of them, I want to "start over" because I don't like how tall and thin they have become and want to avoid staking.
I'll help with a few suggestions on pruning. First however, you need to know that those leaves FEED your plant. Topping to make a plant thicker is fine but this usually works best with lots of sun. Your plant is struggling to make enough food for itself. It is long and lanky because it is not getting enough light. The leaves get thin and larger to be able to have more surface area with which to do photosynthesis. Do not cut any more leaves from your plant. The leaves make carbohydrates from the energy of the sun, or light. Take leaves away, you are taking away the food making factories of your plant. Not that critical out of doors but indoors in 'deep' shade is a big deal.
Okay, see the 'stubs' where you cut? Cut stubs off all the way to the main stem supplying water and nutrients. When you cut back always chose a bud that will grow outwards and away from the center of your plant.
Otherwise, pruning will not help you much without more light. Trying to grow plants indoors that are meant for flowers or fruit is not going to be successful without adding artificial light. Also, you need to be aware of daylight versus darkness schedules. Pollination needs to be enhanced by you with a paint brush or a way to get pollen to the pistil. Reducing nitrogen relative to phosphorus and potassium is critical to produce more reproductive growth instead of vegetative growth.
I like your landscape btw outside that window. Very inviting. What are you using for fertilizer? Have you had any flowers?
How aggressively probably depends on how strong a root system the plant has. I'm in Brisbane (so subtropical) and I have wanted to remove a number of chilli plants, which I usually do by just chopping the main stem off at soil level. But invariably within a few weeks the plants always sprout new stems and leaves. I haven't yet managed to kill a plant this way, but I am in a very warm climate and the plants in question are usually quite well established (in pots), with plenty of healthy leaves, and stems usually at least 5mm in diameter when they get lopped.
For a less well established plant, such a complete "prune" could be too much. So really it depends a lot on how well the plant is doing.
