Yes, worksheet B is appropriate.
You’ll need to do as much investigation as you can into your ex’s finances to prove his true income to present at the hearing. The child support guidelines discuss income from self-employment as follows:
“Gross income from self-employment, rent, royalties, proprietorship of a business, or joint ownership of a partnership or closely held corporation, is defined as gross receipts minus ordinary and necessary expenses required for self-employment or business operation. Ordinary and necessary business expenses do not include amounts allowable by the Internal Revenue Service for the accelerated component of depreciation expenses, investment tax credits, or any other business expenses determined by the court to be inappropriate for determining gross income. In general, income and expenses from self-employment or operation of a business should be carefully reviewed to determine an appropriate level of gross income available to the parent to satisfy a child support obligation. In most cases, this amount will differ from a determination of business income for tax purposes.”