HTC set the fuel burn rate at 2/1 for game balance. If set at 1/1, we would find short-legged, high performance interceptors over bases 100 miles from their take off field. Thus, you don't see swarms of La-7s two sectors from their base. A big part of the balance issue solution is that most want to get to a fight ASAP. It works because most players firewall the throttle and keep it there all the way to the destination.
If you want to fly those types of fighters that don't have a drop tank option (La-7 and Yaks for example) long distances (comparatively), you must accept the fact that the ingress and egress legs will take longer to do so. Just open E6B and take a look at the various power settings. Normal power still burns too much fuel. So, depending upon the range you need, you select the power setting that best suits your need. Just keep in mind that an La-7 will burn down fuel at a very fast rate using WEP. So, leave yourself a good margin for combat. In many cases, you can double your range using the most efficient cruise setting. Also keep in mind that when you decide to RTB, you won't be able to power back until clear of the enemy. So, factor that into your fuel plan too. In bombers, speed is your best defense against interception. So, most players will not use fuel saving power settings. In the case of bombers, the player is already resigned to a long flight to and from the target.
As to how to set cruise power... In the real world, you would throttle back first, and then adjust your RPM. Likewise on power-up, you would first increase RPM and then add throttle. Do either process in the reverse order, and you risk over-boosting the engine, which can cause detonation and result in damage.
This is not the case in Aces High. The engine cannot be damaged. So, you may use whatever sequence you prefer.