Yah! I have actually reached out to both of them already. The prices are great, but delivery time is where I got a bit discouraged, because they don't keep them in stock. So far, my eyes are pointing to this seat: https://japan.webike.net/products/21231067.html It's a bit flatter than I want, but the shape is what I am attracted to. But, I am still trying to figure out in which direction I want to go.
Plenty of time. As you can see there is a lot of advice on getting the bike up to a maintenance level to make it reliable. Not saying it isn't now but it is an ongoing thing to get these small issues out of the way. Being able to ride it while any upgrades are being done in-between times while waiting for things to arrive, helps to enjoy the bike and maybe in that time an idea will change or solidify. Just changing the bars first before the seat, gives the bike a decidedly different perspective and may make a difference to your minds eye on the seat.
seats in that link look thin.
Here is what my son has done to an 83. Just a mock up on the seat. he hasn't made up his mind fully, but is leaning towards the Texivina seat.