Excellent questions, thank you for asking.I did both over years in my experiments, both are effective. Both can manifest outcomes. Mostly, if I work with a sigil it is part of a larger procedure, but only charging a sigil with intent/energy as standalone is effective too. Only focus on a desired scenery works too. There is no best way, only a personal level of experiences.
I am not a resultlike-magician only, I am proceslike-magician also (and maybe foremost) This is partly grown over years out of the experiences I had from the young age, partly it is in my praxis because I am a firm believer of developing my praxis as a holistically thing. So gaining knowledge about my magic and myself as human and witch by operating magic processes. Changing due to training to become more skilled and a better version of myself is a huge part of my path. So that is why I experimented a lot with methods. I write here methods because a lot of people like/recognize that word, but IMHO it is much better to talk about states of being. Working with focussing accumulated energy on a sigil recalls for me another state of being than focussing it in a visualisation/scene, or focussing it in words to make an enchantment of it, or focussing it in a more complex ritual, or focussing it in magic geometry. So every magic working has its own state, its own process, its own learning curve, its own things deep in the unconscious that becomes activated and provides a mirror.
The actual charging of the sigil starts for me already in the drawing process, I push out the energy that I recalled/accumulated in my body while drawing in the actual sigil. If it is about charging the sigil, there is an interesting topic already with lots of inspiration, the search function is at your service for that. Latest used method/state here was holding the little paper with the sigil in my nondominant hand while pushing out energy and pushing it with my hand in a pile of snow as long as I could widthstand, and left it there. But just build up energy while gazing the sigil till it dances in 3D for your eyes is perfect also, is has not to be heroic every time, both its own kind of gnosis.
Oh, and about imagining the energy. I don't imagine energy flow, I feel it happen, I see it happen. I feel how it opens all channels and pores, it just happens at will. For people new to this is making psi balls a good starting point. (But I can't remember the name of the instruction about it that we somewhere have on WF, so the search is not at help now)
