You can use a shot pattern if you choose but with a weighted jig it's not necessary. It's especially not necessary when overloading your bobber a bit like it sounds you are doing. If you do choose to use shot, you will wanted to downsize your egg weight and make up the difference with the split shot.
For casting my recommendation is to start your cast slow and build up speed through the arc. Avoid flinging and/or whipping. Also, add a bright, contrasting corky under your bead but above your bobber. This corky is used to identify if your Terminal gear is fishing properly or not. If it's standing on your float, you should be fishing properly. If it's laying in the water then you are probably tangled and need to reel in and recast.
With drift fishing you need a decent amount of current that pushes or drifts your gear along the bottom. Drift fishing also allows for your gear to be presented to a fish slower since it is ticking along the bottom. A bobber with a suspended setup will be pushed through some of these areas too swiftly and it doesn't give the fish as much time to see or take your offering if they choose. Bobber and jig setups are typically better in slower water, deep water, snaggy bottoms or when the water is low and clear like in the summer or even last week.
There are always exceptions to the generalities so don't be afraid to experiment and try different stuff. That's how all these techniques were developed in the first place.