The king can pay himself a salary of

63 gold.

In what follows, I will refer to the 65 citizens by numbers 1-65. The king begins by

giving his salary to 1, then repeatedly confiscating the salaries of all citizens with two gold and dividing them among the citizens with one gold. This continues until citizens 32-63 have two gold, and citizens 64 and 65 have one gold. The king then confiscates the salaries of citizens 32-63, one by one, and divides them between 64 and 65.

Now citizens 64 and 65 have 33 gold each. The king takes 64's salary, and gives one gold to 65 and another to 1, and then takes 65's salary and gives one gold to 2 and 3.

This is optimal because

at least two citizens must vote for any proposal which decreases another citizen's salary, which means that at least two citizen salaries must increase, and in turn that at least two citizens are being paid at all times. If those two are both being paid one gold, then the last change must have been either:
- give some of those citizens the king's gold (prior to which at most one citizen was paid), or
- give those citizens another citizen's gold (prior to which only the losing citizen was paid).
Both situations are impossible, so at least three gold must be paid out.

The king can pay himself a salary of

63 gold.

In what follows, I will refer to the 65 citizens by numbers 1-65. The king begins by

giving his salary and the salaries of 1-32 to 33-65. The king then divides the salaries of 33-48 among 49-65, then divides 49-56 among 57-65, then 57-60 among 61-65, then 61-62 among 63-65, and finally divides 63's salary between 64 and 65.
For the final touch, the king confiscates the salaries of 64 and 65 and gives one coin each to 1, 2, and 3, securing a salary of 63 gold coins in seven budget proposals.

This is optimal because

at least two citizens must vote for any proposal which decreases another citizen's salary, which means that at least two citizen salaries must increase, and in turn that at least two citizens are being paid at all times. If those two are both being paid one gold, then the last change must have been either:
- give some of those citizens the king's gold (prior to which at most one citizen was paid), or
- give those citizens another citizen's gold (prior to which only the losing citizen was paid).
Both situations are impossible, so at least three gold must be paid out.