Augie used the wisest method to get grass shrimp established.

Going back and reading your fishery goals: "I'm in the process of building a .4-.5 acre pond with a max depth of 10-12'. My goal is to raise eating sized bluegill, and some decent 2-3# large mouth bass."
Then IMO You really do not need grass shrimp to achieve growing high quality fish for your stated goals. Your primary 1st concern is to stock proven high quality fish from a reputable grower or supplier and not something bought off a traveling fish truck. Ask where the stocker fish came from and what is known about the genetic background of the fish.

2nd concern is seek and find pellet raised fish that you buy. The larger the stockers are the more habituated they are to eat pellets.

3rd is to buy the appropriate sized stocker fish for the time when you stock them. Do not by the smallest size of the species available as those are likely to be the runts and slower growers which is usually the small size available in spring. Also smallest fish have the least time trained to eat pellets which means they may not resume eating pellets very well - poorly habituated to pellets. Pellets grow fish better compared eating grass shrimp.

4th is feed the fish a high quality fish food such as Optimal Bluegill or Purina sport fish food. Best first year plan is to buy some (1/2 bag) high protein food from the supplier of the fish. For your small pond I would not buy a whole 40-50 lb bag because you will only need 12 to 20 lbs of food for the rest of the year of feeding for the 0.4ac new small fish pond. It is best to not store and use fish food for over a year old.

Because you are somewhere in TN and if your really care about getting your pond started off very good, I would at least contact this TN pond company for an opinion and an estimate for getting your fish; even if you have to drive 3 hrs to pick them up. I agree with his stocking strategy and pond start-up philosophy. He is reputable for quality fish and concerned about his reputation for growing quality fish.
https://www.trophypond.com/pond-stocking-tennessee-fish-stocking

See his referenced article near the page bottom about grass shrimp – note in the article they are usually associated with abundant vegetation. Vegetation is a key item for grass shrimp success.
https://www.trophypond.com/resources
Article Quotes -
"They reproduce and survive best in the weedy habitat found in many ponds. They do not become abundant when stocked in larger lakes and reservoirs-or in ponds containing sport fish and few aquatic weeds. adults can be caught in May and June by seining or dip-netting in weedy areas of ponds, ditches and streams. They are not common, however….. In August 1973 we collected 81 bluegill from a pond filled with aquatic vegetation. Most were less than 5 inches long, but some were as long as 8 inches. Shrimp were present in the stomachs of 64% of the fish,"

IMO you are best spending your money on better quality fish and high quality fish food to produce quality fish compared to trying to establish grass shrimp in a new bare bottom pond.

Keep us updated as to the progress of your pond.