There's no real easy answer for this stuff. To arrive at a good answer you'd need to understand a whole lot more about programming and really have a handle on where you are currently.
Just to be clear, in trained lifters protein turnover baselines within 72 hours (muscle repair complete or the vast majority of it - often it will baseline sooner depending on what exactly was done). The uber long recover periods that Mentzer quotes are all on untrained lifters. Once you start training your muscles get conditioned due to repeated bout effect.
The real limitation in overtraining faced by most people is the nervous system. Think about the symptoms - disruption of sleep pattern, slowed reaction times, general performance decrement of up to 15%, inability to concentrate. That stuff is not at the muscle. Overtraining is all about the nervous system. Given that the muscular system and nervous systems cover and decay at very different rates, people will exploit this. Basically fatigue is accumulated (that high volume workout that rocked for 2 weeks and by week 6 almost killed you) but can be dissipated quickly. The decay ratio is generally around 3:1 so you could tolerate a much higher volume over a short period (say 3-5 weeks) than could be tolerated over a very lengthy one (8-12 weeks+) and then a week or maybe 2 of lower workload (weight might still be high but volume might be low) would allow recovery. What you wind up with is much higher average workload (stimulus) over longer periods thanks to the undulation and taking advantage of the recovery relationship. And for the record, the stimulus at the muscle is mechanical work. It needs to be decently heavy (measured by the variable intensity as a percentage of 1RM) and you need to do enough work with it (volume or total number of reps performed).
Now back to training, thinking about fatigue accumulating, start thinking about stimulus not just workout to workout but as a block of workouts. Frequency is not an absolute - it distributes workload over a period. So take your 6 sets of 5 reps at 85% 1RM in the squat on Monday - you can only manage that once a week. Well, what if you did 3 sets of 5 on Monday and 3x5 on Thursday. That's equal workload and 2 sessions. There won't be additional fatigue and in actuality most find that they can start raising workload again for a higher average. Frequency is not in isolation, too many people try to do 2x per week and double weekly workload by doing the same workout twice. Even if they could eventually tolerate that, unless they are sandbagging you won't be raising it 100% instantly without additional accomodation.
No thinking about Repeated Bout Effect (RBE), conditioning, and delayed onset muscle soreness (DOMS) - what happens when you do a brand new exercise? You get really sore. What happens when you take an exercise where you do 2x10 and all of a sudden do 8x10? You get really sore. Why? Because you aren't conditioned to the stimulus being applied. What happens when you take that new exercise and do it 1x per week for a while? You get a little sore for a day or so but nothing much (you are more used to or conditioned to) the stimulus. Ask any of the people in this forum who squat 3x a week how sore they get? Answer will be that they don't. Yet they get bigger and stronger, most at rates far faster than what they did before. In other words, DOMS is a self fullfilling prophecy and isn't a good indicator of when it's okay to train again (the less you train, the more DOMS you have, the less you train). Your muscles don't even need to be fully recoverd at all times to benefit from another dose of training. Think about tanning, do you bake hard once for a long time, burn, go back to pasty white and then tan again or would it be more efficient to tan a reasonable amount but with more frequency and not insist on returning to pasty white?
So those are some of the issues in programing and organization. There's simply more to this than going into the gym, doing some stuff, and hoping to become better for it. The further you progress the more planned the stimulus will need to be (or alternatively many just keep jacking their drug dosages to get decent results from a crappy stimulus - this is possible in bodybuilding because hypertrophy and hormones are so tightly linked, in sport with a performance criteria growing muscle isn't enough).
To your original question. Anabolics help with recovery. To varying degrees they are also active on the nervous system (i.e. many experience improved concentration when supplemented with testosterone). So you will no doubt be able to handle more that you normally would. How much is impossible to say and how you should optimally structure your training to get that "more"...you'd have to know a lot about yourself and programming to begin with as well as how you react to a given dosage and how much "more" you can typically tolerate.
That's a long answer but that's the best answer you are going to get even though it's not what you were looking for.
If that type of stuff interests you and you didn't fall asleep, you might also read through this document:
http://www.geocities.com/elitemadcow1/Topics/Training_Primer.htm