LG may seem expensive when you buy it, but that can goes a LONG way. It'll last me over a year on both Bonnevilles.
You'll have to strip your current wax before you apply it. LG isn't a wax, it'* a polymer. You can wax OVER it if you want, but not under it. Dawn dishwashing detergent (a couple washes) should strip your wax. Polishing compound shouldn't be necessary, but you might want to do that anyway and/or claybar.
Being a polymer, it'* more likely to hide small surface scratches in the clearcoat than a traditional wax will. It'll also be easier to buff off (by hand). No buffer is necessary. Wait 4 hours between coats, and 'sun baking' will give you a much better finish by the second day. It needs time to cure.
The instructions on the can are very well-written and should get you what you want.
I did a long-term wax test comparing LG to Mequiar'* Gold Class. There'* no comparison:
30-day pics on page one, 90ish days or so on page 3.