Well I say stick with the conventional "go for it on the hole shot" and the whole first lap if you can. Passing other riders, while fun, costs energy and often forces you to take a less than an ideal or efficient line (because the rider in front that you are trying to pass has already taken that line). So I guess wherever in the group you are, getting yourself as far ahead as you can at the beginning is the most efficient strategy, because you'll be doing less passing, which is inefficient. Since cyclocross doesn't really involve drafting, being in front and fighting off challengers by staying in the most efficient line and finding that extra bit of energy when needed to prevent being overtaken is more efficient than being the overtaking party who has to find the extra energy to pass and take an alternate line.

Yeah maybe you'll be "punching above your weight" by sprinting at the start, but so are a lot of the guys around you. Also after that first lap, everybody is winded so in a sense it costs more for them to attempt to overtake you. So you risk less by slowing down at that point. It helps me with my mental toughness to feel like ok I've invested in this position, and I'm not giving it up dammit. This attitude helps on the final lap when you are trying to tap deep reserves to keep going. Although it's daunting, cyclocross races are short bursts of high energy and as folks say: did you feel like fainting / throwing up at the end? Good, then you're doing it right. So how do you make sure you arrive at the finish line with nothing left in the tank? Easy - overdo it at the beginning and then force yourself to hang on for the rest of the race. Don't give up any riders without a fight. We need motivation to keep going through pain and exhaustion. If you've already given up at the start, where do you find the willpower to tap those reserves? I guess if you know you are going to finish at the bottom regardless, then not killing yourself to get nowhere in the first lap could make sense.

Hey I'm a newbie, there are more nuanced approaches to energy management and I'm sure elite riders that ride races twice as long as mine have more complex strategies, but I know how I can get to the finish line exhausted!