I do (did) have a LOT of 7:00. I was very lazy with manual stretches at first, and concentrated mostly on jelqing and squeezes. That got me about 1/2” of length gain. Unfortunately (or maybe not), it also got me 0.7” of girth gain. I believe my quick, early girth gains may have inhibited subsequent length gains, because I haven’t grown since.
If you want to avoid repeating my mistake, I would suggest doing some hard manual stretching, straight out or straight up, in addition to LIGHT jelqing. Emphasize the stretches. They’re boring as hell to do, but many people have said they can be very effective for newbies. Pull hard, but don’t hurt yourself.
Take careful measurements. If you find that your length starts to plateau after 3 months or so, consider adding hanging, again at high angles. Once your LOT comes up, add some between-the-cheeks hanging sets to pull out those tunica gains.
Of course, if girth is your primary goal, go straight to jelqing. Work up slowly. After a few weeks, you should be able to apply a great deal of force. Work at high erection levels, but avoid anything over 80%. To me, that means never jelq with my penis pointing above the horizontal. Be very careful with this. A blown out vein will set you back several weeks.