What claiming 99 will do (did do?) is reduce your taxes on your income (regular paychecks) so you get the bonus paid out over the year in small amounts.

If you're changing jobs, and expecting a bump upwards in pay, just be sure to withhold your tax liability for the previous year, so that if you end up owing on next years' tax filing you won't have to pay the penalty for underwithholding and you should be good.

That said, the TCJA did away with exemptions and changed the W-4 dramatically. Are you sure you're current on the latest W-4 questions?