Crusting is only part of the problem. Allot of practitioners are bogged down with the watering requirements of their trees. I say this in all confidence as we read it daily that for whatever reason substrates are modified, bigger pots are used etc... to meet our demanding schedules, whilst the solution is much simpler than we think.
For folks that water twice a day, this should not take more than 2 x 30 minutes if done properly, morning and night. If your substrate requires a more frequent schedule, then by all means vary its composition to meet your growing climate. The pictures provided were the result of improper watering not the components. If you can't give your trees an hour of attention daily, then perhaps it is time to pursue a different hobby (I hate that word). Seriously now, if you cannot properly water your trees daily, then how do you expect to look after the maintenance requirement of your trees outside of watering? Come on now, this is a no brainer.
Many have written how to properly water in the past and I shall echo their recommendations once again. Prior to watering the soil needs to be primed. If one was just to water their trees, regardless how well the mix drains, you will set up tiny streams in your soil where water will take the apth of least resistance and out the bottom, leaving dry spots as depicted above. The soil is primed by applying a small coating to the surface and allowed to penetrate and soak. Think of this as a first kiss not dissimilar to kissing a girl after a first date. As that kiss was extremely important to be done correctly, so is the introduction of water to the soil surface, thus priming it.
Priming the soil can be done in several ways, it is important to moisten not wet the soil. This can be accomplished by either a quick sweep with a watering rosette, or what I prefer a mister. Just getting the surface damp and allowed to soak for 5 or 10 minutes, now go take your shower. I prefer a mister (available at Lee Valley (photos attached)) because it does the job admirabvly well of getting the surface just damp. After your shower, give your trees a watering, not too much as we still do not want to set up litle rivers in our substrate, now go have breakfast. After breakfast, armed with your rosette, drown your trees foliage and all, for 5 minutes or so. Your trees are well watered. Don't worry about drowning them if your soil is what it is suppose to be, you have only given your trees roots and oxygen shower. It is the moisture retaining component (s) of your substrate that will replace moisture loss through perspiration throughout the day, not the morning watering. Trees are not on IVs and will only replenish fluid loss as they get thirsty.
If you still can't accomplish this, then set up an irrigation system, more to follow.