i think its better if those plants were in seperate pots, the roots can get tangled and the plants also fight for water,i read that on this site but im no expert
Water them until there is some runoff. 1/4 gallon seems quit a lot to me. When I do my feedings every week I put 1 gallon of water and my nutrients. With that 1 gallon of water I water my 5 plants that are in 3 gallon pots until runoff and normally I have about 1/3 of a gallon left