HI. You seem to be really trying to tackle the very high insulin in a very sensible way. Yes, you must seriously reduce the carbs. Set yourself a daily limit below 200gm and probably 150gm max. You will need to reduce the insulin as your weight and blood sugar reduce. AS your insulin resistance fades with weight loss your insulin stability should get better. I check my Basal in a fairly crude but adequate way by keeping my fasting blood sugar between 5-7 mmol. I make any changes one unit at a time over a few days. Yes, I would have the Basal at night or morning (or both if split). The rapid is taken at mealtime. BTW think carbs not calories if you want to lose weight and blood sugar level; carbs are the villain!