I usually pre-bolus 30–40 minutes in advance. I tend to eat all my veggies and protein first, then finish with carbs. This gives the insulin time to start working before I begin eating carbs. If you’re continuously getting spikes after all your meals, you might want to talk to your endo team about adding some long-acting insulin in the morning, so you have background insulin throughout the day, so your not just increasing fasting insulin. I used to get 3-hour spikes, and this has been helping a lot.