Safety around permanent trickle/float charger connection for car battery

I rarely use my second car, as a result, the battery often drains too much by the time I need it. I have a slow charge battery pack which works if I want to wait a while to get to the minimum level to turn over, but I wanted something to ensure my car is always ready to go so I purchased a trickle + float charger for my car.

Right now, I am using alligator clips with the hood open because I am concerned about gas/sparks. The charger system I purchased came with permanent clips, but I can’t figure out the best way to attach them (they are full circle, not semi-circle). The permanent ones look like they should fit around the screw used to hold the wire clips to the battery terminals. However, when I tried to fully unscrew the nut wouldn’t come all the way off and I thought this was by design.

What I would like to do is to charge the battery with the hood fully closed so the kids don’t try to reach inside. I was concerned that using alligator clips with the hood closed would be less safe (more likely to spark/combust gases), but I am not sure how to best attach the permanent wiring.

Here are my main questions:

1. Is it safe to charge using alligator clips with hood closed? If not, is it safe with the permanent clips (or are these actually only for something more exposed like motorcycle?)
2. If I can keep the circle clips connected, it is okay to have the wire sticking out the side of the hood all the time (if it reaches) as long as I put the weather proof cover over?

If not, its not the big a deal for me to pop the trunk and disconnect before I go.

Right now, I only connect alligator clips with the hood open when the kids aren’t home and then disconnect. I don’t always remember to plug it back in. Appreciate advice on what is safe and best way to setup an easy to connect/disconnect option.

Here is my setup: