This post got me thinking. The beautiful thing about chaos magic is its flexibility, and there's absolutely no reason to be unsettled by its lack of structure because this way, you're free to give your sigil magic operations any framework you like. Accordingly, there'd be nothing wrong with performing a traditional banishing before and after a sigil charging or ritualising the entire sigil creation process, e.g. by soliciting the aid of an entity. The heady days of late-1970s radical iconoclasm in chaos magic are long gone. It's no longer punk's "Break every rule!", it's more like a postmodern "No, thanks, there are a couple I'm actually quite fond of but I
will blast some inconvenient other ones to kingdom come!" You can be as subversive or conventional as you want to be, anything goes.
Accordingly, tinkering with Spare's/Carroll's classical methods and questioning their premises is only logical (and again, no one has the right to force you to start tinkering or questioning!). For example, I quite like the suggestion of skipping the customary charging process, instead framing the sigil and hanging it in a prominent place. You may be reminded of its purpose the first twenty times or so when seeing it (a big no-no according to the classical method) but after a while, you'll hardly notice it anymore. However, your subconscious will, and in this way the sigil will become imprinted on your mind over time. Neat.
Which brings me to another special feature of chaos sigil magic: in my mind, the above method is mainly good for long-running processes, e.g. a consistent effort to become physically fit, and perhaps not appropriate for specific one-time results. Some chaotes don't like the term 'reality engineering' but I think it's very apt. It was the late Gordon White who popularised the idea of 'sigil shoaling' where you charge and release several sigils simultaneously in order to tackle a wished-for result from multiple angles, a good idea when circumstances are more complex. Adam Blackthorn came up with the 'cascade' where you break down the achievement of a given goal into several steps, creating several sigils as well but then charging them sequentially; the tricky part of course is to avoid defining the path to success too narrowly and thus excluding other alternatives of manifestation. To this end, many chaos mages take probabilities into account and factor in potential obstacles to overcome as well. It's not like asking an angel or demon for a boon - with sigil magic, you have to think things very carefully through regarding how exactly your desire is most likely to materialise.
I might be fairly alone in this but I regard the 'reality engineering' process as part of the magic already. Your brainstorming for ideas may create the first magical stirrings within the fabric of the universe, and it might be a good idea to proceed with a positive, determined mindset (include any New Thought methods you like!).