Add the bacon to a large nonstick pan set over medium-low heat. Cook for 10 minutes, stirring occasionally, to render the fat. Pour the bacon along with the fat into a 12-quart stock pot and set over medium heat.
Add the garlic, celery, leeks, and onions, and sweat in the pan for 10 minutes.
Add in the potatoes and raise the heat to high. Pour in half of the wine and cook for 5 minutes.
Add in the chopped clams and clam juice along with the bay leaf, rosemary, and thyme. Bring to a simmer. Reduce the heat to medium-low. Add cream and milk, and continue to simmer for 10 minutes.
In a separate pan set over medium heat, add the butter, and then whisk in the flour to make a loose roux. Cook for 5 minutes stirring constantly so it does not color.
Increase heat on the chowder and whisk in the roux in batches until completely incorporated. Stir in the hot sauce and pepper. Simmer for an additional 10 minutes to remove any raw flour flavor.
Just before serving, place the clams and the remaining wine in a sauce pot. Cover and steam to open over high heat.
Add the whole clams to bowls of chowder as a garnish, and serve the chowder with warm sourdough bread.