I think the difference appears to be minimal and you can just leave it.
Take a tile and place in on the denshield so it overlaps the drywall and place the edge trim behind the tile, if the gap between the back of the edge trim and the drywall is an 1/8" or less it will be fine.
A little extra thinset will fill the difference in the depth.
The extruded ...
Here is the thing - if you wanted it OCD perfect then the tub should have been level. I for one would not cut the tile with that small of a difference. Alaska Man has the right method with furring strips but I am going to answer your question how I would do it.
Within reason - 1/8" for sure - I would widen the gap of the first couple at the bottom to ...
I do not set the bottom row first. I start with the second row and tile on up.
I use a ledger board ( a straight furring strip or 1x2 ) at the correct height so that the bottom of the tile of the second row is slightly lower then the height of the tile that will be the first row. You need to figure out the correct height to place your ledger board. Make ...
This will be a matter of opinion but my opinion would be to have at least 1/8" spacing between tiles. You want enough space for the grout to grab onto. If you're using a contrasting grout for a designer affect, then a larger spacing could be used.
You really have two general options for a "seamless" transition from tile to plank.
Basic "L" trim - pictured below. You will need to install this about 1/8" from each and caulk in between. It should be installed slightly LOWER than the height of the planks and tile - 1/16", 1/8" be OK. Your two floors must be pretty ...
A short term solution is to build a water tight covering over the wall (assuming the shower pan is functioning).
An example (functional and ugly) is to glue FRP Wall Board ,connectors and caulk.
cut FRP Wall Board to size
glue FRP Wall Board with caulk to existing wall
caulk all joints generously
when redoing the ledge add a greater slope towards the ...
That layer below is likely the normal tile adhesive.
The grout is the finishing layer above that, so that broken or missing part should be regrouted.
There are tools for removing old grout. You can do as little or as much as you feel you need, but I would just repair faulty sections if there are only a few. When most are faulty then you have to do all of ...
With such small tiles, you will want to bond those completely to a backer board. So, your options would be as follows:
Shim out the studs so that you can install a backer board down to an
1/8 inch above the tub rim. They make drywall shims that are commonly
available at hardware stores for this purpose.
You might be able to use a foam backer board, such as ...