The technique is exactly the same for all the back windows using the Claytonrite style rubber,I normally put the join at the top but side is OK too.
I prefer to do this as at the bottom causes a potential leak point. imo.
IF you cut the rubber perfectly square at each end and oversize the rubber length slightly, the join should all but disappear and oversizing also allows for some shrinkage.
Make your join in the filler/lock strip opposite the main rubber join too..
As far as lubricant is concerned I use simple alcohol based glass cleaner.
If you do resort to using anything else just try and avoid silicon based products.
I've even heard of folks using 'personal' lubricant....whatever works!
You may already have seen this but just in case you haven't it might help.
Rear glass install on AD truck. Good luck.
