Actually there is not really any tweaking to shotshells other than trying different wad cups or wad pressure to find the optimum pattern in your shot gun. Shotshell reloading requires you to walk on a finer line less room for error than metallic reloading. And reloading steel shot is a even finer line. The reason shotshell reloading doesn't allow much room for error is most shotguns according to SAAMI specs can only handle up to 12,000 to 14,000 PSI most loadings never exceed 10,000 PSI but if you use the wrong grain charge to wad cup combinations it is much easier to exceed extremely high pressures. For example I use federal hi power rolled paper base shells with 20 grains of green dot with a wwaa12 white wad with a 1 1/8 oz shot. with this load if you just change say the you use a different wad cup then what the load data calls for you could actually increase barrel pressures to dangerous levels. Most people reload shotshells to get premium ammo for bulk price. But if you are not into competition trap and skeet I just recommend buying bulk trap loads from walmart besides those sell for cheaper then you can reload for. The heavier loads like turkey loads are even more risky. Asfar as improper wad, hull, and charge combinations. Basically its easier to blow up your gun if you don't pay attention to what you are doing. But once you get the hang of it and know what you are doing. its alot of fun and if you keep an eye out for good deals on components you can reload for cheap. If you do get into shotshell reloading I recommend starting out with 2 3/4 Winchester AA hulls Because there is tons of load data for them and components more readily available. Start out loading light field loads till you get the hang of it. If your uncle knows how to reload shotshells make sure he explains and runs you through it first I deffinately do not reccomend just jumping into it without any kind of guideance first. Heres some load data for a good starting load this is the same load I started my brother inlaw with when he wanted to learn shotshell reloading, this load is great for dove, quail, rabbit , squirrel and even pheasant. My brother inlaw has killed turkey with it too but I recommend no shots further than 20 yards on a turkey.

Hull: 2 3/4" winchester AA, Primer: Winchester 209, Wad: WWAA12 (white), clay buster makes an equivelant for cheaper it is called WAA12 (white) replacement, Powder charge: 19.5 grains of Alliant Green dot, Shot weight: 1 1/8 ounce. I would use either #6 or # 7 1/2 shot pellet. this load is a intermediate velocity of 1200 fps just a good all around load.
Note: I would use no wad pressure let the weight of the shot produce the wad pressure, Because I've noticed if you apply tomuch wad pressure you run into crimping problems. and less wad pressure also reduces recoil.