I am first time diy installer, need help in figuring out how to transition from hardwood to linoleum.

We have an "open concept" master suite that features a master bedroom leading into a bathroom area and then a walk-in closet. Nothing on the other side of the closet.

Master BR and closet were previously carpeted. I've ripped that out and installed 3/4" hardwood nail down on insulayment (about 1/8" thick underlayment). The bathroom is linoleum over 3/8" plywood. There seems to be about 5/16" height difference between the hardwood floor and the top of the linoleum.

On the closet side, the planks are parallel to the doorway (which has a door). I started that room from the far wall and ripped the final row at the doorway to about 1/2" from the linoleum. So no tongue and groove available there to fit any transition piece to.

On the master BR side, the flooring happens to be perpendicular to the threshold to the linoleum (no door, just an arched doorway). The planks end in more or less straight line with the end grooves facing the linoleum.

The flooring company sells 3/4" "flush reducers" but they are 1/8" on the other side, and are 2-1/4" wide. How do I make this fit? I was thinking:
- Rip cut until the thin side matches the linoleum height
- Cut the linoleum + plywood back a bit so the reducer fits. (Can't really just ride the reducer on top of lino as I would have if it were a T-molding).
- Let the transition piece be flush against the hardwood and linoleum?

I have a vague feeling I need to leave an expansion gap on the closet side where the boards are parallel and the nails are in the direction where there is a strong chance for expansion. But not sure what to do really, originally I thought I was going to put in a T-molding kind of thing that was shorter on one side, so just left some gap. I haven't been able to find such a thing unfortunately. I could also just install more plywood in the bathroom and more lino on top, bringing it to same level and use T-molding.

The flooring company also has "overlap reducers" but they seem to be max 5/8" and I need 3/4". I read somewhere that these are used for floating floors so I'm wary about using them.

The problem is, I don't know if I'm close to being on the right track or completely off .

Also any thoughts on what would happen in this open concept situation where the shower/tub could throw a lot of steam and humidity into the air (we were not using the bathroom during installation and haven't done so yet due to all the furniture stacked up there).

So would appreciate any inputs.

Ewwwww no doorway to the crapper? Anyway, sounds to me like you are going to have to modify an available threshold to meet your needs, but also, from your very clear description of the situation you are facing, you have the ability to do this. Also, unless the walk-in is very large, expansion shouldn't be too much of a factor, but you should still allow for some minor expansion due to the proximity to the shower.

Hehe just so it doesn't freak you out, bathroom = tub in the open + shower with a fuzzy glass door, and opposite side sink + "crapper" *with door* .

Thanks for confirming the rip cut etc.

Re: the expansion, how do I leave the expansion, the reducer would be flush against the wood (has groove to lock into the tongue actually). So you have plank - reducer - lino all tight against each other. I guess that would not work, so I'm better off just raising the bathroom floor and installing another layer of lino/tile/whatever, and then use a T-molding with the nice expansion gap under?