I use a garden shredder as a scratter. I made the top slot wider to take full size apples and found that I scrat apples as fast as I can feed them in. I have a plastic paddle to push down any apples that get stuck in the top hopper on to the shredding mechanism. The shredder can easily handle in excess of 50kg of apples per hour.
If your lucky you can get one for gratis off Freecycle.org, or relatively cheaply off eBay. Most shredders can be taken apart and the metal parts scrubbed to clean them up. Soaking the parts in full fat coke will also help clean them up. Post usage you can strip the parts out, wash them and then dry them and then store in cooking oil to prevent long term corrosion.
i used to scrat into builders trubs and then build cheeses wrapped in muslin and separated by boards. My press is a cross beam and 6 ton bottle jack.
The pressing was the slowest part and each pressing took around 15 to 20 minutes to load, press and unload. I was getting around 10 litres of juice per hour.
i found that for 10 litres of juice I was getting around 10kg of residual pressed scrat. Assuming 1 litre of juice weighs 1kg the system is around 50% efficient.
I read that apples should be pressed immediately after scratting, but pears should be left for 24 hours before pressing. I found with pears I would get around 15 litres of juice for 5kg of residual pressed scrat, i.e around 75% pressing efficiency. I’ve tried leaving scratted apples for 24 hours before pressing and it increases the juice yield, but it comes out much darker and feels quite thick and syrupy, it also taste very sweet.
Having been in touch with other forum members, and as a trial I changed my method to scratting directly into a 25kg washed, boiled, and oxy bleached Hessian spud sack and pressed this between 2 boards that I placed in a pressing bowl.
The pressing bowl is a stainless steel beer barrel with the bottom ground off and then inverted and pipe work connected to the tap hole, through which the pressed juice drains into the collecting vessel.
I found that using this method I can get around 15 litres of juice from 2 pressings in around 15 to 20 minutes.
Whilst this methodology may not be as efficient as freezing, freezing/scratting it is so much faster and much less time consuming.
I store my apples in banana boxes, that I got (pre COVID) from my local supermarket, for a couple of weeks before scratting. I’m convinced that storing them increases the yield. The boxes stack and so take up very little floor space.
I can get my hands on large numbers of apples so 50% efficiency I consider to be enough.
I note that you said you shake the trees. If you can get your hands on a hard hat, it saves any surprises during this process.
