Is it permissible for me to receive a percentage of money in exchange for providing alternative laborers to carry out delayed work on a project supervised by my company, with the head of the laborers being aware of this percentage, and is there a specific percentage if it is permissible?

There is no objection to charging a commission for finding workers if this is not part of your primary job, and the commission is by agreement. This falls under the category of permissible brokerage, provided that the person paying the commission is aware of it.

However, an employee is not allowed to request a commission from the workers or the entity executing the work without the permission of their employer, to prevent any suspicion of favoritism towards the person paying the commission at the expense of the employer.