No CT, but I'm in week 2 of Phase 2, of that program. Here's a little of what I've been doing:
For the HFST I do SGHP, Front Squats and low DB Incline Presses. I dislocated my shoulder and partially tore my deltoid last year, these exercises are the ones that I can do 5x a week without too much discomfort or aggravating my shoulder. This part takes between 30-45 minutes. I like to do jumps and some light mobility work between sets, to better warm up. Regardless of what you choose for the HFST, start light, much lighter than you think you should. It builds in intensity and volume through the 12 weeks, and the goal is to nail every rep with perfect form, not to be grinding out reps halfway through the program.
The circuits are hardest the week you start the program. I was fairly surprised how quickly my work capacity increased. That said, their effectiveness is determined by how hard you work. If you're just going through the motions in round 4 because you're tired, it won't be nearly as effective as if you consistently push yourself. I don't have access to a prowler or battle ropes, my replacements have been airdyne or erg rower, and doing high rep renegade rows, respectively. Not ideal, but it's something. I also do a set of crunches to failure during the rest between rounds. I took this from CT's old Ab Shredder plan, and it seems to be working great.
As far as weekly structure, I go Mon, Tues, Wed, Fri, Sat. I would give the program a shot for a month before ever worrying about adding extra days. Week 3 is especially difficult. I've also been walking on the treadmill afterwards, anywhere from 20-60 minutes, depending on the time I've got. I like drink MAG-10 during the walk, seems to kill a lot of birds with one stone. Oh and I recommend using Indigo and Plazma, intra-workout. It's a ton of volume, and I prefer to go heavier on the circuits, Plazma will save you from over-training like you wouldn't believe.
Hopefully that helps. Let me know if you have any other questions.