Hi, we are changing a vanity top and sink in a 1980 period house. This one is at parents house and so I'm trying to make sure I know what I'm in for before getting started. The current plan is to add a new top that would have an under-mount sink. The new sink height is just under 8"(eight). Given the height of the waste pipe exit into the wall and the alignment of the plumbing, I sense there isn't sufficient height to make things fit. With the bottom of the sink being 8" and considering the need for the stopper part of the drain part, seems there isn't going to be enough space for the trap. I realize options are likely to a) use a different sink and/or b) get into the wall to lower the height of the drain (assuming it is possible). Anthing else obvious i'm missing on this? I"m attaching a picture for clarity. Thank you very much for any input.