What amount (percentage) of disposable income is required to enroll in a debt management plan?

Tough to say without any details. Found this calculator here.

https://www.debtconsolidationcare.com/calculator/debt-consolidation-types.php

Try it once. I think you'll get an idea.

What is your current income status? If you are still facing financial hardship and you have huge debt, then talk to a debt counselor to get the best-suited repayment option. You will get an idea of personal financial budgeting as well.

What is your total debt amount? How much do you think you can save from your monthly income?
Please follow this link - https://www.debtconsolidationcare.com/debt-management.html, I think you'll get what you need to know about DMP.

I agree with Phil. Debt consolidation is better since you'll be paying back the debt completely. However, settlement has its own advantages.
It is better you talk to a company and then decide whether consolidation or settlement works best for you.

I've never heard of anything as such.
You go for a consolidation plan because your income and lifestyle can't handle your debts! Even if, any debt consolidation company do ask for some sort of requirements, then probably you will have to follow such rules. Otherwise you are most welcome to do a DMP.
Then again, why DMP??? If you believe that you don’t have adequate income, then choose settlement man!!! You will save a lot …!!!

And you can ask a consolidation company any sort of questions you have… They ain’t gonna mind nothing!!!