Every year the same question: how much salt and vinegar to add to pickled cucumbers. So, once and for all, here is the time-proven recipe:

Cut the cucumbers (peeled and seeds removed) in approx. 1 cm slices and cut in half.

for 1 L of liquid, take:
25(-35) g of salt
(17-)20 g of pure acetic acid (i.e., 80 g of plain 25% concentrated white vinegar, or 400 mL of plain 5% vinegar)
20 g of sugar
4 g of “Gurkenfest” — this will make the cucumber pieces firm and they will keep for a long time
Add some pepper seeds, bay leaves, as you like. I don’t add much.

Alternatively, you can also use 35 g salt, 17 g of pure acid content, for a more salty taste (I prefer more acidic taste for these cucumbers).

Boil thoroughly for 6 minutes at least.

Fill into jars (sterilized by boiling in water for some minutes) and close immediately (turn upside down, let it cool down).

Better not to prepare more than about 1.5~2 L at once, otherwise it is difficult to fill the jars fast enough, or the cucumbers may be overcooked, unless you are working in a rush.

1 L is typically enough for 1.5 kg of cucumbers.

Surely you could also fill the jars cold, and sterilize 25-30 min at 85-90°C.