The carpet has arrived, time to shim.

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I'm planning for options on a rather high shim to tile. Tile cut nice and sharp, no bevel at all.
The home is expensive. The carpet ridiculously expensive and the builder like myself, pays attention to details.
Here's what I picked up at the job site 3 months ago when the carpet was ordered.
There are 5 bedrooms, all butting to 3/4" engineered wood. Everyone was happy with this edge.

 

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I had the carpenter install 1/4 inch plywood in all the rooms to bring the carpet level up to the point where the mockup I made would work.
I went back down as per the carpenters request. He was installing door jambs and wanted to come straight off the tile in the bathrooms into the carpeted area. He asked me to come back down because he said that he "could" notch out and lower the jambs if I deemed it necessary.
Well holy crap, the tile it a full 7/8+ inch tall....... not like the wood to carpet doorways.
I figured the tile would be relatively close to the wood height. He said they added heating cable. Which might explain the taller height.
The carpet is woven wool and about 3/8" thick.
Here's a sketch, close to scale.
If I start my doorway shimming with 3/8" plywood across the opening, it will be like this.
The lower sketch is if the tackstrip is nailed normally.
The upper sketch shows a thin shim under the tackstrip for fine tuning.
(Continued explanation follows)

 

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The issue will be a full 3/8+" inch slope up into these bathroom doorways with a flat looped pile carpet. The contractor wants this elevation difference to be unnoticeable to the customer. The sharp, square tile edge is not helping.
I have a couple of options sloshing to and from in my brain.
At the door opening jamb edges, the height will be 3/8".
If from that 3/8" strip in the doorway, I add a one foot wide piece of 1/4" underlayment, followed by one row of VCT, I'll have created a taper to float out with filler.
This will create a quick 3/8" downward taper from each door casing across the baseboard.
Also, when you enter the room, a couple steps later you're walking up the ramped part to the bathroom doorway area.
Here's my first idea for a ramp.
Walking into one room is a window and an 8' wide sliding glass door, which amplifies any hump in the floor.
Option two will follow.

 

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Here's my other thought.
Still use the 3/8 strip in the casing area and 1/4" by 1' wide plywood as before, but continue the VCT all the way across the room. From there, I could feather out a foot and a half. I wouldn't have to ramp up, then ramp back down across the door opening. 1/8" would be much easier to make "invisible"
Picky? ....Oh yeah, were being picky.
Nothing else in this 5500 sq ft house is more than 1/8" out of whack so I want this as good as it can get. Yes, he's paying me so this isn't a freebie.
This option makes it a quarter inch rise instead of a 3/8 inch rise, then 3/8 inch decline across the bathroom doorway.

 

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Here's option B with the VCT going all the way to the wall. The bathroom doorway is shown, there is a portion of the hall door casing on the right.

 

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The contractor called and he's still working on the rooms that previously had no underlayment. In those rooms, instead of 1/4 inch, he installed 1/2 plywood.
In the room that had 1/4 inch underlayment, he added a second layer of 1/4" , so all 5 rooms will have the equivalent of 1/2" .....thicker than I'd prefer for the wood transition, but not so much shimming for the tile. I'll find out when I get there later today.

 

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Well, he's one sharp contractor. He watched and listened as I was describing the tile height issues a month ago. He took it up on himself to add a second layer of 1/4 inch underlayment in the two rooms he had done at the time. He hadn't started the other two, so he just bought 1/2 inch for those. He had the sample board I had mocked up 4 months ago and took it up on himself to just raise the subfloor a little more. Not so high that the carpet to wood transition was screwed up. He did great.

The largest, the master bedroom is the only one ready. It's 18 by 23 plus a 7' 6" by 10' 6" walk in closet. I barely need to shim the tile..... Maybe one or two layers of poster board. The wood won't need any.
In the other 4 rooms, two will be perfect fitting to the wood and the other two meet some sanding to reduce the height a tad..... Slightly less than 1/8 inch.
Tile transition looks almost perfect in one room, two rooms won't need much, but the last one is tapered across the doorway.
It will need almost 3/8 shimming on one side and 1/4 on the other..... That one will need creativity.
Tile is still being installed the showers of those 4 rooms, so it might be a week or more before another room is ready for carpet. The pressure on me is off, so I can take my time on the master BR.