We're pulling out everything and replacing the rotted subfloor and 1920 plumbing, then putting it back together and making it pretty. Note that this is a house that when fixed will be worth $60K or so, so we want to make it look nice (I will be living here for a year or so) and stay period as much as possible, but we're not spending a fortune.

Question #1: Which is better for a tub: acrylic or enameled steel? Pros and cons of each?

Question #2: We could just cover up the window, but if we keep it, what's the best way to waterproof it? Mr. Weedy saw a made-for-shower window at Lowe's that's vinyl with glass blocks inset. Other things to consider?

An enameled steel tub will be stronger than a acrylic tub, if you buy a quality one, i.e. American Standard Cambridge.

Any chance you can rearrange the fixtures inexpensively? Maybe turn the tub so you can put the window above, say, the toilet (moved)?

It's not so much the window, but that it's a double-hung. The flat top of the lower sash can collect water. In old houses where the double hung wood windows had to stay, I'll bevel the top of the sash for drainage.

The better bet in a shower is a vinyl window, and the way I prefer to waterproof them is to use a topical membrane. If it's a Kerdi Shower I'll use strips of Kerdi and Kerdi Fix, using the K-F to adhere the membrane to the window's vinyl jamb.

If a Hydroban Shower, I'll still usually use strips of Kerdi and K-F. I always have scraps around. I like the way the Kerdi sticks (stuck with K-F) to the vinyl window jamb, then transitions out and over the face of the cement board lining the shower wall. Then I'll HB the cement board, overlapping on to the Kerdi that's around the window jamb.

There are other ways. But that's what I prefer.

Your "shower window" at the box store might make things easier.

Tentative plan on the tub is Redguard and tile. Don't own any kerdi scraps, but maybe I can wheedle some from a local tile store.

I'm thinking if we keep the window, we at least need to make it half the size, so it doesn't start down so low. That just looks weird.

Back to the original question - IMO, porcelain on steel feels and sounds tinny while quality acrylic or cast iron are both OK for tubs. However, you are selling it rather than living in it long-term, so cast iron is a safer bet to appeal to buyers.

Our needs:
1. Can't be a water collector.
2. Needs to minimize work/cost involved so must be the size of the current window or smaller.
3. Has to look decent, and be period to the extent possible and inexpensive.

So what would you do:
1. Cover it up and be done with it (Mr. Weedy's vote)
2. Replace same size with glass block? stained glass? etched glass? openable or not? (don't know that I would ever open the window while showering)
3. Replace with something smaller (close up bottom half)
4. Leave as-is, and just perhaps etch the top half.

I found some cool designs on etsy that I could probably get for around $100, that use vintage depression-era glass plates. Here are some examples:

What think you? Is that lead between the glass panels a liability in the shower? Or is there a way to make this work?

I needed privacy. The stainglass options you show would be beautiful, but this film may meet the need too, and be easy to install. I don't know how it would work in a very wet situation like a shower. The line I purchased was a vinyl cling that used the tension of water to hold it in place. There are some that use an adhesive. I was very pleased with the process of buying and receiving the product. The installation was easy and the product included good instructions and "tools" to install the film.

We replaced with a vinyl interior, and pebbled privacy glass. Entire window is removable for cleaning.

Wedi board all around sill, edges… and then whatever else husband did… then subway tile all around edges… and very narrow marble sill.

Here is the window originally. You can see that the PO had built out a ledge to get away from the window, which we removed… plus, you can see the tub, which was my first introduction to a luxury edge… it’s only a few inches, but it’s surprising how much more roomy it feels to have those few inches between you and the wall… plus, puts room between you and window.