I don't think it is a waste of time, but you need to get the diet in order first. The PHs will help you maintain muscle mass while in a calorie deficit, but at that BF I would not be trying to bulk up with them. Get the diet in order and start slowly increasing your cardio. When you start losing the fat and you feel that you can continue on with the new eating and cardio lifestyle, then the PHs will come in handy to keep you from losing the hard earned lean muscle mass while you shed the fat.
Before I used any PHs I was at about 26% BF and got my diet and training in order. I dropped about 10 lbs and 2% bf to 24% and then ran my first PH cycle of 1T/4AD transdermal (S1+) for 4 weeks. I really had my diet in order and ate very clean and I gained about 14lbs but dropped 2%bf to 22% on the cycle. I waited about a month and a half after PCT and then started my cutting cycle where I used Mdien the 1st 4 weeks and just finished 4 weeks of PCT. On the cutting cycle I dropped 26lbs so far but my lifts in the gym have dropped very little. More so now since I am not on anything, but I compensate with intensity in the gym. I have not checked my bf in a while, but this cutting cycle so far I have lost 5 inches off my waist and I hope to see my abs sometime next month.
The whole thing depends on your dedication to maintain a strict diet and never missing your gym sessions.