AUM, being AU - gold - in the periodic table, also works with the Solar/666 Chakra, which is the powerhouse of the Soul and in one sense is the most important Chakra. If we strengthen our Solar/666 Chakra, this is helpful in results, plus this Chakra also is to help us regarding being bothered and actually working, instead of being lazy and apathetic. AUM can also be vibrated into the Aura, as well. As you said, AUM can be used to empower workings more, and you can also use SATANAS, vibrated [hiss]ayyy-taaa-naaa-[hiss]. SATANAS is also very powerful and can be used for more or less anything, irrespective of other Words (but other Words, i.e. Sanskrit Words or Runes, are specific/more direct).
I believe AUM is the top-level of AUM; there is nothing more powerful or stronger with it, other than vibrating it more times - the same with SATANAS; SATANAS is the top-level of SATANAS, and vibrating it more is more powerful - if you are able to concentrate and handle more repetitions, of course. Also the use of power numbers is very important; 9 is a super number regarding power, which not only has permanence in terms of endings, it can also help to break down walls/barriers, as well. 3 is the number of creation/destruction (which also multiplies into 9); apparently, 108 has now been revealed to be a bad number to use, whereas 54 and 216 are fine. 8 is the number of eternity. 13 is a number which I think ties into the number 4, which is of Satan. 111, for example with SURYAE, ties into the Sun (SURYA/SURYAE is the seed mantra of the Sun), so I think also vibrating AUM 111 times, or multiples thereof, can also be of benefit. I have seen some say they do, or would try to do, 666 vibrations.
For each Rune, they can be vibrated these power number of times or vibrated the number of times of each Rune respectively. More vibrations equals more power. It's OK to start small/low and build up higher, but staying small/low won't get you very far. You might get some results but they wouldn't be very great. For more severe problems, higher numbers of vibration multiples are needed and doing perhaps 2 times 40 days in a working and/or doing the same working twice per day - once in the morning and once in the evening. Again - if you can handle it.
It is recommended to start and finish with AUM and/or SATANAS - but certainly finish with them, and as far as I have seen the recommendation is to vibrate either or both of these once; vibrating them 3 or 9 times, for example, surely would help more - but as long as you can handle it. It is better to build yourself up to a higher number of vibrations, than to start high and try to manage it.
