Age: 19 years old
Height: 6'0
Weight: 217
Bf%: 12% (estimated)
LBM: 191
BMR: 2240
TDEE: 3865
TDEE @ 20% deficit: 3092

I figured that I'm going to follow a carb-cycle of 4 low carb days followed by a high carb day. I will do cardio every day except for the days I train legs.

Now - my problem is that I'm not sure whether to base my protein/carb/fat macros based on a certain number * LBM or deriving from 20% deficit of my TDEE (3100).

LOW-CARB DAYS

Carbs
I plan on taking 54g carbs from oats in the morning, and 82g sweet potato in my PWO meal (BCAAs and aminos for IMMEADIATE PWO nutrition).
Total carbs = 136g.
136g = 17% of 3100 calories.

Fats
I plan on taking 3g fish oil with every meal except PWO, I would take more but I don't have enough money to buy all the supplements I want and 4 bottles of fish oil as well, plus the food. So that makes up for 21g of fat per day, I plan on taking olive oil/nut based oils with my 6 meals that don't have carbs (8 meals per day). I'll consume about 120g fats per day.
120g = 35% of calories.

Protein
I have no problem here - 50% of my intake will be from protein.

HIGH-CARB DAYS
My question here is - should I continue to have my intake at 3100 calories or should I keep my protein/fat macros the same while tripling my carb intake to 400g?