I know just enough to know what I don't know. And that includes not depending on manufacturers and marketers for technical expertise. For the rear wheel/front wheel question, I do understand that rear discs are used rather than front discs because front discs impair steering. But the relative effects of rear wheel and front wheel profile on overall drag is not something I've seen discussed by independent experts (and I don't count cycling journalists as independent experts. I prefer reading what the engineers have to say, preferably publishing in the peer-reviewed literature). If somebody has a pointer to something pertinent, I'd appreciate it.

On a tangential subject, the tendency to wider tires that marketers are selling ignores the importance of having a narrow tire in the front where the width of the bluff body matters. Most of the advantages of a better ride from a wider tire comes from the rear. Thus, quoting Hambini "From an aerodynamic perspective, the width of the rear tyre has little effect but the width of the front tyre has much more impact and therefore a 23mm front tyre is recommended irrespective of whether the wheel was designed for 25mm tyres. At speeds above 30km/h, it is more beneficial to have 23mm tyres than 25mm front tyres for aerodynamic benefit."