Yes, I like using the old MC34063. Its a relatively simple chip. But don't get stuck on the semiconductors. The coil is the main player. And real inductors behave a lot differently than ideal inductors. More so than capacitors and resistors, when comparing the ideal model with the real parts. For power applications, the inductance changes (to a lower value) as current increases. This happens well before the part goes into saturation, so any calculations made, are just a first stab. In reality, you may have to go 2 to 4 times higher, than calculated.
In practical matters I like using coils with E3 values (E3 meaning significant figures of 10, 22 & 47). With the MC34063, I can change base frequency with the timing cap. Smaller caps can be found, cheaply, in a wider range of values (E6 - 10, 15, 22, 33, 47, & 68). E12 or higher only with resistors (E12 - 10,12,15,18,22,27,33,39,47,56,68,82).
You can get more power out of an SDR1806, but before going there you aren't get all the power out of the RLB9012. If you can't easily change frequency, then increase the inductor size. Buy some 220uH coils, though you should be able to get more power out of the 100uH part. I routinely get more than 30mA out, at nixie voltages.