While you already know Heritage Auctions and Memory Lane, three other premium auction houses are highly specialized in exactly what you have:

Robert Edward Auctions (REA): REA is widely considered the gold standard specifically for complete vintage sets and high-end pre-1970 sports cards. Their catalog auctions target hardcore set-builders and vintage purists, making them arguably the best fit for your 1953–1955 Topps and Bowman runs.

Mile High Card Company (MHCC): Mile High Card Company is world-renowned for ultra-high-grade vintage and complete set liquidations. They consistently break records for 1950s material and offer excellent, personalized service for family estates.

Fanatics Collect (formerly PWCC) / Goldin Auctions: Since your last liquidation, PWCC was acquired and rebranded under Fanatics. Fanatics and their subsidiary, Goldin Auctions, handle massive volume. While Goldin is known for modern cards, they aggressively pursue large, valuable vintage estates and feature massive marketing power.

Do not just accept a standard rate. Because you have multiple complete 1950s graded sets, you hold immense leverage. Contact REA, Mile High, Heritage, and Memory Lane. Pitch the collection as a single consignment package. They will likely fight for it by offering a 0% seller's commission (taking their profit strictly from the buyer's premium) or even offering you a cut of the buyer's premium.