Stocking a new pond (no fish) is entirely different from stocking into a pond with adult and sub-adult fish.

In the south spring stocked BG at 2 inches in a new pond will (assuming good nutrition) spawn (first hatch) in a couple of months at 3-4 inches. LMB 2 inch stockers can not eat the 2 inch BG but will eat FH fry and by late summer will be eating the first hatch BG. You change the equation by stocking a few 4-5 inch BG with the initial 2 inch BG stockers. You speed up the hatch process as those few 4-5 inch BG will spawn in a week or so thus providing a early first BG hatch that small LMB can eat.

Unless you want to play the numbers game (can be done) then stocking into a pond with adult/sub-adult predator fish (LMB etc.) works better with adult stocker BG. They cost more but don't get eaten in the first week.

In any event it is wise to habituate any fish stocked into a pond with existing adult predator fish.

Northern ponds are different with regard to stocking BG and LMB. Timing is different.