Using welders cable, you can also include a welders cable twist dis-connect (in the trunk).
As for location, take advantage of the location BEST if you have set of 4-wheel scales... you can easily see how the location changes the 4-wheel corner weights. Originally, I installed the battery above the axle... then later relocated it to the pass-side rear corner as it helped with the 4-wheel corner weight distribution.... scales can become another tool to have in our collection!