Would you use the link with the crossbar always, or if it meant less real estate was available inside the chain, use one of the links further along the chain? Which increases my risk more?

Right now your rear wheel looks available for a simple theft. Unless I was staying within sight and was keeping an eye on it, I would remove the front wheel, pass the chain through it’s rim and lock it and your rear wheel’s rim (within the rear triangle) to a well anchored post, bike rack or even medium sized tree. This method generally minimizes chain through your bike allowing you to go around larger anchors. If I had enough chain, I might go around the anchor twice to take up some slack or tighten it up minimize exposed links. Thieves will have no other option than to attack the lock or the anchors of the bike rack or to steal any accessories you leave on it.