I've been sub 8% for most of my life actually, as a boxer for 6 years eating 5k+ calories a day the entire time, and spending upwards of 4 hours in the gym 7 days a week. When I quit boxing I went on a long time bulk, so my details are mainly for this current cut. I put on over 90 pounds of mass (intentionally) over a 4 year period. When I hit my goal weight of 250 I started cutting and here is what I did.
250 @ 19% BF to 220 @ 9% BF
Cutting @ 3400 calories with 40% allotment for protein and the rest from whatever
Exercise:
Chest + Triceps + Biceps
Back + Shoulders + Traps
Legs + Abs
1 day of cardio max effort HIIT hill sprints
I guess I probably did an unintentional carb cycle during most of this, but it really was unintentional. I would occasionally eat less almonds/fish and eat corn or potatoes or something. I didn't keep exact intake stats, but I am good at guesstimating my caloric intake and deciphering where they come from predominantly.
Supplements:
Ephedrine (went from 24mg per day to 72mg per day) + Caffeine + Yohimbine in the form of Dexaprine XR.
Pre-workouts varied, but because of the large amount of E + C + Y I usually do/did non-stim Hemavol/Compete combo.
Fish Oil, Multi-vitamin, and copious amounts of Isotean.
My current avatar is of me a few weeks ago @ 224, I'm 221 right now and have not lost an iota of strength (hit my previous PR on DL three days ago same weight I got at 250). I think the key was that I cut very slowly understanding that it is not a sprint but a marathon. I will soon start bulking again (leaner this time) when I reach my desired BF.