Question for the Fat Fire Community - Gifting Money

We're at the point that one of our children and spouse are about ready to buy a house. We want to transfer between $200,000 and $250,000 to help them with the down payment. We understand that my wife and I can both contribute the maximum gift to our child and partner, and do it again after the first of the year, to get close to the $200,000 goal, but it doesn't quite get us there.

As a matter of logistics, what is the best way of gifting that amount of money to them for a home purchase? We would like to gift them a block of stock. How do we account for capital gains if we transfer stock, rather than cash? Is there a more efficient way of transferring the funds to them than simply gifting them a block of stock?