Alrdybig,
Not a big gainer yet, but perhaps I can offer a view on your questions, although you sound fairly knowledgible already.
As to the breaks, less is more, and if you can bear to take two rest days off after every one exercise day then that is good. Do this for a few weeks to see whether you can go further. If your erections suffer, then take even more time off. People heal at different rates, so mimicking a big gainer does not always result in success. You may even find that you end up PEing nearly every day with very little rest. Experiment, and take your time.
As to the healing of damage. In the first few months or so of your PE career you may wish to allow complete healing before more exercise is done. You may change this later, as many believe that regular exercise will keep the penis healing in an extended state, but you must be conditioned first. The best advice anyone can give you is the listen to your body.
Finally, although you want lenth only, I would still suggest light jelqing as it has the potential to improve your erections, and also I believe that stretching and other exercises may involve scar tissue being created, which would limit your capacity to gain, and maybe even get an erection. Some believe that light jelqing can ‘break up’ this tissue and allow full expansion. I leave that to your reasearch however!
Again, won’t include my schedule, as I’m not in your big gainer club! :o