I’m happy to read that you found Humulin R works well for you. Many people who eat limited carbs will often use Regular insulin to dose for low carb meals with a significant protein content.
I have had problems in the past honoring the longer onset time of R vs. rapid acting analog insulins. One time, while waiting for the needed 45 minutes to begin eating, I fell asleep in an easy chair and woke up on the floor due to serious hypoglycemia since I failed to eat the meal I dosed for. I know this is an extreme experience but it does point out that adequate pre-bolusing of R requires a more watchful eye on the clock.
Good luck with your continued success with Humulin R!