Hi Perry ! Welcome aboard! Sounds like your into the outdoor cooking scene like I am.
With your mention of a 7lb brisket, I have to assume that it's a center cut (trimmed flat cut) separated from a fairly large full packer. I have smoked up a ton...well, a couple hundred pounds of brisket, either as whole packers, or with the point and flat cuts trimmed and separated, and occassionally, in-home brine/cured brisket flat or point.
The following are links to a few of the brisket projects I've done since I've been a member here on SMF. All include methods, pics and recipes:
Here is a trimmed/separated full packer smoked in a smaller smoker (Brinkmann Gourmet vertical charcoal).
Here is a brine cured flat cut, similar to corned beef pastrami.
Here is a somewhat traditional corned beef pastrami (the recipe isn't exactly as a traditional CBP, but it's as close as I could get with what I had to work with).
Here is a more basic brisket smoke.
If these projects seem difficult to accomplish, they really aren't...I prefer the KISS method, but at times I step things up a bit when the urge to push the envelope overcomes me...LOL!!!
If you haven't tried smoking brisket yet, remember to be patient. Brisket needs low & slow to get tender.
Also, I prefer not to inject my large cuts with marinades, as this allows you much more flexibility with the danger zone temps/times. If injected, you need to get the internal temp through the danger zone in 4 hours which can require higher smoke chamber temps, thus translating into a bit less smoke reaction with the meat. If it's intact whole muscle meats you need only put it into a hot smoker (~225*) and let it ride through it's journey.
If you've smoked pork butt, you already know about the plateau...brisket point, flat or full packer are just as with any other large cut of meat, so expect that.
Good luck, great smokes, and don't forget to have fun! (I know, you already knew that one)...LOL!!!!!