Dog seeking friend

Hello! My partner and I recently adopted a dog named Hardy from the Everett shelter. He's an amazing one year old lab pittie mix. We'd live in the Lowell neighborhood walking distance to two dog parks. Hardy is non reactive and expresses great interest in other dogs. He would love a friend. We're nervous to just let him loose with other dogs at the park without knowing his history and would love to meet up with someone to make a slow patient acquaintance. Somebody that is understanding if it may or may not go well. Does anyone have a medium size mild energy dog that may want to meet up soon? Thanks for reading!