When targeting spawning bass in the Delta with swimbaits, there are several techniques you can employ to increase your chances of success. Here's a breakdown of effective strategies, some of which are supported by the video context provided:

1. Imitate Natural Prey: As Brian Snowden mentioned, during the spawn, bass are highly protective of their nests and will chase away any potential threats, including bluegill. Using swimbaits that mimic the look and movement of bluegill or other natural prey can trigger aggressive strikes from spawning bass. Choose swimbaits with realistic color patterns and profiles that resemble the local forage.

2. Sight Fishing: If you can visually locate the bass on their beds, as discussed in the Bass University video, you can use a swimbait to entice a reaction strike. Cast past the bed and slowly retrieve the swimbait over it. The key is to keep the swimbait in the strike zone as long as possible, giving the bass ample opportunity to attack it.

3. Weightless Rigging: Rigging your swimbait weightless, as shown in the Bass University video, allows the bait to stay just below the surface and in the line of sight of the spawning bass. This can be particularly effective in shallow water where bass may be more easily spooked by heavier presentations.

4. Slow and Steady Retrieve: When bass are spawning, they may not be as willing to chase down fast-moving prey. A slow, steady retrieve that keeps the swimbait in close proximity to the bed can be more effective. This allows the bass to zero in on the swimbait without expending too much energy.

5. Targeting Transition Areas: As LakeForkGuy suggests, during the pre-spawn phase, bass may be found in transition areas as they move up to spawn. Fishing swimbaits along these routes can intercept bass as they stage before moving onto their beds.

6. Varying Sizes: Depending on the size of the forage in your specific area of the Delta, you may need to switch up the size of your swimbaits. As the TacticalBassin video highlights, matching the size of the local baitfish is crucial. If you observe larger baitfish like gizzard shad, don't hesitate to throw a larger swimbait to match the hatch.

Remember to adjust your tactics based on the behavior of the bass and the conditions of the day. Sometimes, it may take a few different presentations to figure out what the bass are responding to. Always be prepared to switch up your approach if you're not getting bites, and pay close attention to the bass's behavior to inform your technique.