I like the second one but with thicker shoe trim (larger quarter round). When I did what you're doing, I found that the larger trim could sit on the hardwood because it was thicker than the original ( I assume the hardwoods were put in after the trim and that's why the trim sits below the hardwood. At least that was the case in my house). Anyway I very carefully removed the shoe trim and actually reused it. Once I priced good quality trim, I was looking to save where I could.

Good luck! and Yes, it gets very messy in those small spots between door trims.

Go big. Wimpy molding looks cheap. Don’t worry about the doors and windows.

This great blog post that the interior designer Laurel Bern posted on her site about a year ago.

https://laurelberninteriors.com/2019/08/04/best-proportions-for-interior-trim-why-youre-confused/

It's chock full of good information and a lengthy but entertaining read. Laurel has a fabulous wit. She explains in detail how she arrived at these recommendations and she sums things up in this chart:

I have a Dutch Colonial built in 1935. All ceilings are 8' on the first floor and about 7.5' on the 2nd floor. All baseboard throughout is 5 1/2" high. The LR and DR have 4 1/4" Crown. As an aside, I don't like painted shoe molding. I prefer it to match the floor.

Here's the DR. I know the "faux" wainscoting makes it hard to see. The LR has the same proportions without the wainscoting look. I don't have a good picture of the LR.

Here's an upstairs bedroom. You'll see that even with the low ceilings, the baseboard height at

5 1/2" looks fine.

Looking at your pictures I have some thoughts to share.

Whoever put in that hardwood flooring did you no favors. The original baseboards should have been removed and reinstalled after the floor was installed. The door jambs and side casings should have been undercut so the hardwood could have been slid under. That wasn't done. So removing the existing baseboards will be challenging, tedious, and time consuming.

If you go this route, you don't have to lose the full 3/4" inches. You can install the baseboard flush with the top of the hardwood or 1/8 to 1/4 " below the hardwood. One thing you may run into is that today's baseboards seem to be even thinner than what was being used in the 1990's. That means you may have a larger gap between the hardwood and the baseboard for the base shoe to cover. It can also mean that the baseboard doesn't sit flush with the door casing (this would look OK, because it wouldn't be proud of the casing. Proud of the casing = bad).

BUT, you have other options which would allow you keep your existing baseboards intact.

One option is not to remove the existing baseboards but to add an additional molding profile above what's there. When it's all painted it looks like you have higher baseboards. That's what was done in these photos:

This will substantially reduce both time and material costs and yield a great look. There are tons of molding profiles available.

There's another product that's made that fits over your existing baseboards. I think it's still made, I've never used it. The challenge you'll run into is at the door casings - it will stick out further than the casings. The solution I've seen is to cut back the casing and install what's called a plinth block. All together it looks like this:

Anyway, some things to consider.

None of that style looks "transitional" to me, including, fake stone cladding, oak floors, wood railing. Having said that, colonial fits for baseboards.

Thanks Missenigma for sharing photos, and the molding looks great in your house! It’s always helpful to see pic examples in peoples houses. I will have to look at the article as well. I actually looked for that molding that goes over the existing molding before posting this but unfortunately it’s it of stock or from sellers that are not well known to me.