What are the plans for this art?
Train it. Since we can do so passively after the first level, train it till then ASAP and let it accrue on its own from week to week unless we really want the goodies it offers for a specific task.
We were told we can go up to three meridians on the first floor, so two is super safe unless you're looking for an exotic element. The jump off point for between first and second is a three meridian art using two different elements.
Why specify all three meridians though?
Like, even if we assume that 3 meridian up-front arts are just better, which isn't necessarily going to be true really, it makes a lot more sense to say, "three meridian arts including at least an arm meridian" If anything, it makes significantly more sense to specify one meridian and the elements that actually work with our gear/affinities/other investments (e.g., water, wind, moon) vs a combination of 3 meridians that we hope does something specific.
As to how many options we can expect.... We have 6 types of meridian: Head, Lungs, Spine, Heart, Arm and Leg. That's 6 1 meridian types, 6*6 possibilities for 2 meridians and 6*6*6 possibilities for 3; or 258 combinations of arts up to 3 meridians (252 if no art uses only 1 meridian in its fully learned form). There are 8 conventional elements (and many others). So, we're up to 2064 arts if there is exactly one art of each element at each combination.
Ling Qi found the first few that she could locate that only took a single heart meridian. There are upwards of a hundred art scrolls on the first floor
Note, Yrs has described the size of the first floor as 100+ arts. That suggests 1/20th of possible 3 meridian/element art combos, and less than half of the potential 3 meridian combinations.
So, specifying an exact breakdown of meridian usage, there's a roughly 50% chance, based on WoG that we won't find an art on the first floor of the archive. This assumes that every art that is there uses a specific unique combination of meridians without overlap, which almost certainly isn't true. It's much more likely that some combinations are common and a good number of weirder ones don't exist. We have very little data as to what combinations are common.
Note, that a random combination of meridians may not have the specific effect we want, and, given that we're probably going to want something yinish, in an element such as water (for dress) or wind (for affinity/weapons), most of them will be discardable, as elements that don't match your gear, or the rest of your set, are shit for direct combat where qi efficiency is king, and diversifying gear and art discounts as much as possible just dilutes actual combat power dramatically.
By contrast if we look for "powerful direct attack arts of either wind or water element" we're both telling the QM much more directly what we want to find, cutting out misunderstanding, and getting ourselves a range of elements we can actually use.
So yeah, pretty sure we could look for a three meridian heart art on the first floor and find several, never mind a two-er.
Note, ZB uses 2 meridians in full. There are, actively, drawbacks to arts that need more meridians to slot at low levels. We haven't really seen examples with clear benefits for having more frontloaded meridians, except perhaps, more at the first level, which doesn't really help if we want to get all the levels of arts we invest in heavily (Note, FVM used 2 meridians at level 1 and none at level 2, SCS used 1 meridian at each level, I don't think either is definitively more powerful).