With the 90° yellow flame lighter i light it directly above tho the bowl & suck the flame onto the ceramic filter so it's just about touching it, it's harder than the arc to get a steady flame on the ceramic filter but it's much more visual as you can see the flame dipping in. I've only just seen the red glow, which is also a good visual point to know when to back off. I get the glow with both lighters so they are just as good as each other really, but they both have different advantages, like the 90° piper lighter has more light  but the arc is more consistent in its contact with the ceramic filter.

The way you described using the arc & moving it closer while already inhaling slowly sounds good, i can see how that would work well, its not too complicated as it's vital to get this right i feel, i'm going to try both lighters again, i just tried the arc with some cannabis right now & it worked a treat!

The butane in both my lighters is the same, 'Ronson universal gas lighter refill ultra refined' i can definitely taste/smell the arc a little bit more than the 90° yellow flame pipe lighter, maybe it's more of 'heat' taste/smell & not actually gas, i can't taste anything when i actually vape something though, only when it's empty.

After using the arc a fair bit just now i can see how it is safe to use with the GVG, the diffuser loses the heat quite rapidly. I'm also getting the red glowing now a lot, watching for the red glow is a good reference point to start backing off with the lighter.

Right now both lighters seem to be as good as each other, the arc maybe feels a bit more of an elborate ceremony which is always a plus with the spice in my book, i'd say for the rare occassions i use DMT i will use the arc but for more everyday use i'll use the 90° pipe lighter, cannabis also tastes great in the GVG, send me some of your hash plz endlessness that sounds delicious