When installing tile - the subfloor must be supportive so it has limited flex (deflection). This is dependent upon the size and spacing of the floor joists, the span, and the subfloor material.

You need to get the specs from the tile manufacturer - as far as deflection.

A qualified tile setter will determine if your subfloor needs to be improved, or whether you can use that tile.

Schluter makes all sorts of transitions.

Thank you Geoffrey- have you ever seen wood porcelain installed on the majority of a second floor (we don't live near water and it's a primary residence.)

Guess I picture the usefulness in vacation homes but love the lool and we have pets. :)

I don't see what your concern is about whether it's on the first floor, or second floor, or why it matters if you live near water?

I've never seen a home with porcelain tile on 2nd floor...thinking of resale, if it would be a turn off.

Regarding living near water- I would imagine a home with sand/water - tile would make more sense, just trying to decide if we should do it because we like it (which likely matters most) or find a similar color hardwood for second floor and a tile for baths.

Porcelain is just fine on the 2nd or 3rd or whatever floor. You just need to make sure that the subfloor is supportive enough.