Can someone check my coco Drain To Waste $$ Math?

Hi!
I'm new to hydroponics and putting together a system on my porch to grow some tomatoes, peppers, strawberries, herbs and weed.

I've started out with a deep water culture and am now trying to move towards a drip system. I'm intrigued by drain to waste and coco coir because it seems like its much more controllable than a recirculating system. However I'm trying to understand the reservoir size, and nutrients needed for my grow and what cost that might come out to be.

I detail below the parts of the system. I make some assumptions. The biggest one being how I calculate my required reservoir size and feeding cycle. Can someone give me feedback on the assumptions below (specifically the feeding section)?

My theoretical setup:

Goal: Drain to Waste Drip system for 4 tomato plants

Container: 5 gallon bucket
Medium: 5 gallons coco coir/perlite (75/25) mix
Nutrients:
Feeding schedule comes from: https://gh.growgh.com/docs/Feedcharts/GH_FloraSeries-DTW_03216am.pdf

Flora Micro:
Cost: $20/gallon (some deals online)
Cost per ml: $20/ (3785.41 gallon/ml) = 0.00528
Avg Feeding: (2+4+5+4+4+4+4+4+4+4+2.5)/11 = average 3.8 ml/gal
Flora Gro:
Cost: $20/gallon (some deals online)
Cost per ml: $20/ (3785.41 gallon/ml) = 0.00528
Avg Feeding: (1+5+5+4+1+1+1+1+0+0+0)/11 = average 1.7 ml/gal
Flora Bloom:
Cost: $20/gallon (some deals online)
Cost per ml: $20/ (3785.41 gallon/ml) = 0.00528
Avg Feeding: (1+1+2.5+4+5+5+6+6+8+8)/11 = average 4.2 ml/gal
CaliMAGic:
Cost: $30/gallon
Cost per ml: $30/ (3785.41 gallon/ml) = 0.008
Avg Feeding: (0+1.5+2.5+2.5+2.5+2.5+2.5+2.5+2.5+2.5+0)/11 = average 2 ml/gal
Armor Si:
Cost: $30/gallon
Cost per ml: $30/ (3785.41 gallon/ml) = 0.008
Avg Feeding: (0+0.5+1+1.5+1.5+1.5+1.5+1.5+1.5+1+0.5+0)/11 = average 1 ml/gal​

Nutrient Change Cycle: Empty reservoir each week and replace with next weeks nutrients
Hydro Method: Drip Irrigation
Drain To Waste: Yes
Feeding:

3 feeding per plant a day
run off 1 quart per feeding (quart estimate from (Watering Coco - How to Water Cannabis Plants in Coco Coir - Coco For Cannabis))
Total nutrients used per day = (4 plants) * (0.75 gallons per plant) = 3 gallons a day
Resevoir Size Per Week = 7 days * 2 gallons a day = 21 gallons​

Resevoir Cost

ml per gallon: 0.000264172
Flora Micro: 21 gallons * 3.8 ml/gallon * $0.00528/ml = $0.42
Flora Gro: 21 gallons * 1.7 ml/gallon * $0.00528/ml = $0.19
Flora Bloom: 21 gallons * 4.2 ml/gallon * $0.00528/ml = $0.46
CaliMAGic: 21 gallons * 2 ml/gallon * $0.008/ml = $0.34
Armor Si: 21 gallons * 1 ml/gallon * $0.008/ml = $0.17
Total Cost/Week = $1.58​

Cost/Grow Cycle (11 weeks) = $17.38