I too collect these high-dollar issues; both singles and plate blocks. You might want to download my FREE topical album pages for US Priority Mail and Priority Express Mail. The current set is complete through 2020 and has frames for 2021 issues.
You can get it at https://www.thestampweb.com/albums/free-downloads
Scroll down to "USA - United States" and download "USA Priority & Express Mail". If you want just the pages, download the pdf file. If you have the AlbumEasy software, and want to be able to make changes or additions to the pages, download the .txt file. The stamp frames are sized to allow the use of Scott/Prinz mounts without covering the frames.
Here is an example of the album pages from my personal album. The version available for download does not have the Scott numbers due to copyright issues (but you can add them yourself using the .txt file and AlbumEasy). The pages contain full color images for each stamp, but you can also set your printer to "gray scale" to print in black and white, therby saving your colored inks.