Just use powders then. There's very little difference, they weigh less, last way longer, and are easy to mix. I'm in the US and I use powder developers.
On top of that, you don't *need* a rapid fixer for the volumes you're doing - a standard sodium thiosulfate fixer will work just fine and this is easily purchasable as a powder. Mixing is brain-dead easy. The only reason that rapid fixers are liquid is because ammonium thiosulfate is not stable as a powder.
Stop bath? White unscented vinegar. Photoflo? That you should buy in liquid form but a single 500ml bottle of PF will last you literally *years*.
Stop worrying about grain, resolution, sharpness, and everything else that doesn't have a damn thing to do with substance.