RC chargers (and common BMS units) have very tiny balancing capabilities, so with a large pack like yours, if it did get out of balance, it could take days to weeks to rebalance it.
The best way to avoid that is to use the pack well within its performance limits, so it doesnt get out of balance in the first place.
Some info below about that.
I dont know off the top of my head what the Leaf cells you have can do, so well illustrate using some imaginary numbers:
Lets say your pack is 250Ah, and is capable of 5C maximum sustained. That means it could handle up to 1250A, but if you use only half that, 625A, as the max current even for bursts, then it wont push the cells very hard at all, and theyre likely to stay balanced. (assuming they are also charged at much less than their charge rate limit)
However, if its only capable of 2C, thats only 500A, and using only half that, 250A, probably wouldnt be much fun.
Regarding a capable charger that wouldnt cost a lot, the Meanwell LED PSUs like their HLG and similar series are usable as chargers, and as long as their voltages are correctly and equally set, can be paralleled for higher charging currents. A number of us here on ES use them.
I use my Satiator for slower charges, and my lighting pack, but for fast charges I use a pair of HLG-600H-54A units in parallel, adjusted to just under 58v, for my 14s2p 40Ah EIG NMC pack, to get a 24A rate (which is actually higher than the 0.5c rate the cells are speced for, but I dont do it often, just on a rare occasion I need a really fast charge--usually I charge at 12A with just the one HLG bolted to teh bottom of the SB Cruiser trike).
The pack itself I use at a burst max of around 2.5c, though its rated for 5c continuous and 10c burst. Sustained max is much less, around 0.5c or less. I dont normally use more than a few percent of its capacity, either. And it stays balanced without BMS or other manual interference. (as did its predecessor with the same kind of cells, on a previous lighter cargo bike that had lesser power requirements).
Most of the BMS units are made to fix small imbalances in small packs, so they have less than 100mA of balancing current capability. If you have a pack thats more than 200Ah, and it gets really badly unbalanced, so say 20Ah or more of imbalance between highest and lowest cells, it would take a 100mA bleeder BMS at least 100 hours to correct that much imbalance, as the BMS will shut off input current as cells reach HVC, then bleed those down, then let charge current resume until the high cells reach HVC again, etc., repeating until all the cells reach the same voltage (which generally means theyll be the same state of charge, and thus contain the same Ah again).
If the cells are well-matched its unlikely theyll get like this until they get older, or if theyre pushed really hard, or both, so probably not somthing to worry about (but to keep in mind).