Probably the most efficient is shooting smokeless powder and using a dillon 650 or 2nd most efficient Dillon 550. That is expensive.
Over the years I have evolved my processes. Iniitiallly used the lyman priming system that primes as you lower the ram. Filling tubes sucks. Also no real feel doing it that way. Bought a Lee ram priming unit that mounts like a die. Has a large and small primer chute and 2 different pins. Used that for years but, the primers dont always slide down so you sorta need to shake or tap after every prime. Primers can easily flip if they do not fully slide into place to be raised up into the primer pocket. Lee does not make it anymore. Looked at the lee hand primer but it requires special shell holders, not particularly expensive but who needs the additional stuff to keep up with. Bought a RCBS Hand primer last week as it uses standard shell holders. Have not had a chance to really use it.
There is no really efficient method for dealing with bottle necked rifle cases that have to be full length resized. You end up having to trim and deburr. Will not address loading bottleneck rifles.
Tumble all my cases first to clean dirt and dust that will scratch dies. I use a lyman turret press.
De prime,
prime on second press using the lee set up or use hand primer.
I am paranoid about failing to charge a case and getting a bullet stuck in the barrel so I have started batch charging cases 50 at a time and visually checking for powder and powder level.
I then expand case mouth if shooting cast
seat bullet and crimp. Gentle rool crimp on rifles, just kinda take the bell out for pistols unless heavily loaded, I use small amounts of fast powders generally so do not need a heavy crimp to make for a better burn some like to use with slower powders.
use lee factory crimp for auto pistols
Short of using a progressive, using a turret press as a manual progressive is probably as efficient as you can get, but I do not like to prime on down strokes. This necessitates handling the case one additional time
If you use a powder thru expanding die you can charge when you bell the mouth, rotate turret and seat bullet but I have gotten in the groove and occasionally failed to charge a case. Pain to get bullet out of barrel and catestrophic if you fail to notice and shoot another round. Thus explaining why I batch charge and inspect.