The epic battle over the $300 million estate of copper heiress Huguette Clark neared conclusion Saturday as lawyers wrestled with the final details of a settlement that could yield at least $10 million for the cash-strapped Corcoran Gallery of Art.

Clark died at 104 in May 2011 and had no children. She spent the last 20 years of her life secluded in hospital rooms in New York, despite being reasonably healthy and having mansions on both coasts and luxury apartments in New York. She signed two wills within six weeks in 2005. The second one cut out family members and rewarded people she had come to know late in life. It was immediately challenged upon her death.

Under terms outlined in a draft of a tentative settlement, 20 descendants of the first wife of her father — William Clark, the copper baron and U.S. senator who left hundreds of paintings to the Corcoran when he died in 1925 — would get $34.5 million. An arts foundation would be created and receive Clark’s $85 million mansion in Santa Barbara, Calif.; her doll collection, valued at more than $1 million; and $4.5 million in cash for the foundation.

The Corcoran would receive $10 million. In addition, the Claude Monet painting “Water Lilies,” owned by Clark, would be sold and the Corcoran would get half of any proceeds in excess of $25 million. The Corcoran would also have a seat on the foundation’s board.

Clark’s goddaughter and a few longtime friends and employees would collectively receive more than $4 million. But a large portion of the estate would melt away in expenses: $24.5 million in attorney fees and tens of millions of dollars in unpaid taxes, penalties and interest, plus estate taxes.

Lawyers said they expect that a final settlement could be signed as early as Monday.

The Corcoran would receive less than it might have under the will, which would have left “Water Lilies” to the gallery. The work has been appraised at $25 million. Despite that proffered gift, the gallery surprised many parties in the case when it joined family members in objecting to the will. The gallery’s attorneys — who worked for free and will not share in the attorneys’ fees under the settlement — argued that Clark may have been incapacitated, or unduly influenced, and that her true intentions may not have been reflected in the will.

A Corcoran spokeswoman and the gallery’s attorneys declined to comment. Lawyers and others familiar with the settlement talks pointed out that no party is getting everything it hoped for.

The Corcoran needs the money. Annual deficits of $7 million on a $31 million budget prompted it to consider selling its building in 2012. A deficit was avoided that year only because it sold an adjacent parcel to an office developer for $20.5 million. The gallery and related Corcoran College of Art and Design are exploring a partnership with the University of Maryland. Results of those talks were to be announced by this fall. The gallery has been trying to refocus its vision on American art and contemporary art and design.

NBC News first posted the draft settlement document Friday night. People familiar with the talks said that document is several days old but contains the main contours of the evolving agreement.

A primary incentive to reach a settlement was to avoid a costly trial. The 21 / 2-year battle has involved 16 firms. Jury selection began Thursday in New York but was almost immediately stayed by a Surrogate’s Court judge so she could rule on a motion that would facilitate settlement talks. Jury selection is scheduled to resume Tuesday unless a final agreement is signed by then.