I think the best "paleo" meal plan out there is Art DeVany's New Evolution diet. Basically low carb, but he emphasizes the need to eat plenty of non-starchy vegetables and low glycemic fruits, and he combines this with the need for intermittent fasting, varied food and meal schedules, and an exercise program built around intermittent, brief, high-intensity exercise. DeVany himself, at 72 years old, is a walking advertisement for his program, super fit and strong with about 6-8% bodyfat.
In "Why We Get Fat", Gary Taubes addresses precisely your question about hypoglycemia, lightheadedness and brain fog. These are basically symptoms of dehydration. The secret to reversing this to use plenty of salt on your food and supplement with potassium, and drink lots of water. The transition to low carb is associated with a major change in electrolyte balance. Your body transiently loses sodium, potassium and water as a direct consequence of the reduction in insulin levels, and that can lead to the symptoms you describe. Typically, after about one week, you have completed the transition, and as you upregulate HSL (hormone senstive lipase, the fat releasing enzyme) and glucagon, downregulate LPL (lipoprotein lipase, the fat storing enzyme), and adapt your body to running more on fat and ketones.
By the way, the very same effects often happen during fasting, which makes sense because fasting and a very low carb or ketogenic diet result in similar metabolic adjustments.
I don't think it is necessary or wise to go all the way to zero or very low carb to get the benefits of a generally low carb diet. I like occasionally (several times a week) adding carbs into my diet -- either as part of a meal or an isolated small "treat", because I think that carb cycling helps maintain insulin sensitivity. There are reports that holding to a strict low carb diet over the long term can result in insulin resistance.
I follow a mostly Paleo Diet and my insulin level is 4 IU/ml., the same as that of Kitavan tribesmen. Art DeVany's is similar low. Average levels in the U.S. are 11-15 IU/m, and 20 IU/ml is considered pre-diabetic.
Todd