Joesmoe
Unfortunately, as you have discovered, Word treats a ‘Tall’ brochure differently when the Bookfold option is used.
Click the image below to see a short video on how I create a portrait ‘tall’, 4-page brochure on A4 paper. The Letter size should be similar.

First, click the Page Layout tab.
Click the Margins tab and opt for ‘Narrow margins’. You can of course use your own dimensions.
Now click the Columns tab, then the More Columns option.
Click Two in the Presets and the Line Between is optional. If it is used, it can be removed at any time (say before printing) if you require.
Use the Equal Column option which should be selected by default.
Add content to the left column (back - page 4).
Add content to the right column (front – page 1). The center line only appears when content is added).

When the right column, page 1, is complete, continuing with further content creates another page (pages 2 – 3, inner pages) where further content is added.
When your brochure is complete, check the Print Preview - page 1 (4 – 1), then page 2 (2 – 3).
In the print settings, opt to print out Page 1 (4 – 1).
Put the page back in the paper feed tray, upside down and in the correct orientation and in the print settings, opt to print Page 2 (2 – 3) on the back of Page 1 (4 – 1).
When complete, folding the page along its long axis creates the tall, 4-page brochure you require.