A pinch is not the same for everyone!
Feed what your fish can consume in about a minute. If it is hitting the bottom cut back a little. Over a week or so watch the stomaches of your fish, if they pinch in you may need to feed more. Keep in mind if you are overfeeding now, your fish may be fat so don't think that they are starving because they lost a little weight.
Although loaches will eat snails they will certainly pound your shrimp collection too. Assassin snails will work but you will need a bunch to take care of MTS. MTS can easily outbreed a couple of assassins!