Here's the thing, if you gained 30 lbs in a bulk and DIDNT put on a noticeable amount of muscle then you were not generating enough stimulus in the gym to trigger adaptation i.e muscular growth. I.E you weren't working out hard enough.
Without knowing exactly what you were doing diet and exercise wise it's impossible to say where exactly you went wrong, but the fact that you were gaining weight tells me the problem was more than likely in the gym.
So what makes you think that SIX REPS is going to generate enough stimulus to preserve or build muscle while on a cut? The main point here is that for six reps to equal the training response of say 2x15, 5x5, 3x8 etc. those 6 reps need to be HEAVY, and I'm just not seeing anything in your description of your failed bulk that tells me that will be the case.
If I were you I would probably eat somewhere very close to maintenance, i.e if you changed nothing day to day your weight would remain the same and put in a solid 4-6 months on any basic, beginners program that works in a moderate rep range or multiple rep ranges. See what you look like then before worying about 'bulking' or 'cutting'.