2ml per tablet is generally the safe number as the absorption rate of APAP (Paracetamol) is 12.8mg per ml in standard room temperature water, so if you were to CWE all 4 of your tabs use 8-10ml of water, this would mean you would end up with a maximum of 128mg of APAP (Paracetamol) in the mixture assuming you filter correctly and no chunks get through, if the liquids clear then thats the amount you are getting.
(I personally stick the glass of water in the freezer for a few minutes to drop its temp a bit lower but never to the point of freezing before mixing my crushed up pills, colder the water the less APAP gets in and the temp doesn't have a noteable difference on "the good stuff" getting absorbed)
The reccomended dose of APAP at one single time is no more than 1000mg, and daily no more than 4000mg, so you are well within safe levels here, even if you were to just eat all 4 tablets (not recommending) normally you would only be over the reccomended dose by 0.25 times, unlikely to cause any damage to a healthy person, and even more safe to a larger person.
However in the spirit of harm reduction, do not take more than the recommended amount of APAP, shits bad for you, I do the same as you and CWE everything I get which contains it, if you do it all in one it will be basically a tiny shot of clear bitter liquid but the effect will be noticeable within around 10-15 minutes usually.
TL;DR - 2ml per tab, with regards to amount for each example I would just make the full 40mg extraction and dose accordingly, if you want 1 tab, drink a 1/4 of the liquid, if you want all four then down the shot, knowing your own tolerance levels is key here.