I think the veterinary dose of paracetamol is based on 10mg/kg 2-3 times daily (but can be higher for short periods, but I wouldn't use it higher without advice).
Lilly is 25kg and regularly gets half a 500mg Paracetamol (Lidls best

) twice a day, with an extra half if she is limping or going to have an active day.
There is nothing wrong with telling your vet you want to try paracetamol for a while and asking them to confirm the dose you intend to give.
Paracetamol (nor PardaleV) does NOT interfere with NSAIDS though sometimes vets seem a bit vague on that.
There is good evidence that paracetamol boosts the effects of other painkillers.
And that codeine and opiates like tramadol are less effective and also cause tolerance because if their addictive potential if used in THE MEDIUM or LONG term.