FWIW My SO and me are the only people I know who do the allowance thing. My friends routinely talk about "he/she spent so and so much on $USELESS_ITEM, grumble grumble". I say "pocket money!" and they nod and laugh and don't do it because it makes them feel like children.
Doesn't that encourage waste? You seem to have decided that a certain portion of income will just be blown on random stuff.
I go with double-approval. You could call it a veto system. Both must agree before spending.
There is pre-approval for unavoidable expenses like bills, groceries, fuel, emergencies, and tolls.
I agree on budgeting and bookkeeping. Frankly, we do neither. I buy a bigass TV because I want it, my wife buys some awesome workout gear because she wants it. It just works. But yes, it's a position of luxury to not have to budget.