I did the same thing as you with the original Arbiter. Single coil build. It was okay, but it wasn't anything special to me. In fact, I sidelined the atty for 6 or so months because I just wasn't impressed.
Then I got bored one day. I threw a bunch of rebuildables I had laying around on my desk and I started going through them all one by one. Thoroughly cleaned, coils dry burnt or replaced if needed, rewicked, etc. I came across the Arbiter and figured eh, I'm going to throw a dual coil in this and see if it makes any difference.
The difference: Night and Day.
Dual coils have larger chambers to accommodate the space for 2 coils. If you opt for a single coil in a dual coil, you're now created a lot of open space for air to dilute the vapor your single coil is producing and it also changes the path of airflow. With a single coil, the airflow intake is pointed in such a way that it should be no more than a millimeter or two from the coil. When you stick a single coil in a dual coil chamber, you've essentially added at least 1.5 mm of empty space on each side of the coil (assuming the airflow is aimed from the side) allowing a ton of the airflow to circumvent the coil.
If you were to take a look around, you'd probably notice that one of the newest "highly talked about" rebuildables is the Damn Vape Nitrous RDA. What this kit does that separates it from the rest, is it includes 2 top caps that are specifically used for single or dual coils. This was to address the chamber space to coil ratio.
My suggestion would be to commit your single coil to one side so that it's closer to the airflow intake. A better suggestion would be to go to a dual coil configuration, but I realize you're concerned about the juice consumption. Another option would be to shop around for a well-known, good performing single coil RTA.
I will agree that the Arbiter appears to be a juice guzzler (apparently that hasn't changed from the OG to the second edition). I do however think that much of the juice usage is perceived and not actual. If you look at the chamber size in comparison to other tanks,
it's huuuuuuge! (said in a Fat Bas-turd accent). There isn't very much space between the glass and the chamber, which makes the rate at which the juice is being consumed seem very rapid.
From Left to Right: Vaporesso iTank, Hellvape Dead Rabbit V2 RTA, OXVA Arbiter RTA, Innokin Z Force
There's quite a bit of juice that pools down at the bottom of this tank. Like a lot.
If you are looking for single coil RTA flavor bangers that won't break the bank, I'm sure there are quite a few people here that have suggestions for that.
I would recommend:
Smokerstore Taifun GT4 - Clone from FastTech is under $30.
Vapefly Siegfried Mesh RTA - This is a good one because you can try out mesh with this as well as clamp in a single coil if you don't find mesh to be your thing. This is my favorite mesh tank for RDL.
Steampipes Cabeo RDTA - More or less built the same way as an RTA. The tank on this one is pretty small, so an RDL or MTL setup is best (high/higher Ohm, low Wattage build). Clones can be found at FastTech for under $30 as well.
Hellvape Dead Rabbit V2 RTA - Easy to build on, great flavor.
That's all that comes to mind at the moment.