In the case of se-tenants, in addition to space for single stamps, many albums provide room for a block and / or a strip, and depending on how the full sheet is laid out both blocks and strips may be available formats. There may also be space for a full sheet, a souvenir sheet, or a booklet.
As a general rule with se-tenants I mount what I have: block, strip, sheet (Arctic Tundra for example) or booklet pane. I purchase the USPS Stamp Yearbook with the commemorative stamp packet each year and one is not always certain what formats it will contain (blocks or strips). This is one reason why, since 1999, I use Steiner pages rather than purchasing the annual supplement for the Harris Liberty album, as I can edit the format and the layout of the Steiner page with LibreOffice Draw to conform to what I have. I also like having spaces for each individual stamp, where I will pencil in the Scott Catalog number and the stamp design (Steiner doesn't have pictures). If one of the stamps comes in with the mail I'll cut it out (I don't try to remove self-adhesive stamps from paper) and hinge it in the appropriate single space. It doesn't bother me to have many of the singles spaces empty, though I gather from comments that this might drive some here crazy.
I've not yet mounted U.S. year 2003 (need to update my 2000 Steiner CD and the free U.S. pages for download don't start until 2011) but I went to see what I have. The USPS 2003 commemorative stamp packet includes one page from the booklet (2 horizontal strips of 5 stamps on 1 booklet pane), and I have a complete booklet which I would have purchased at the post office.
I don't normally collect full booklets (I'll pull one page out, even if double sided, and use any remainder for postage). However, the Scott 3776-3780 Old Glory booklet is attractive and interesting enough I'll mount it whole. With the other booklet pane I have (2 horizontal strips of 5 stamps), I will probable use 1 row for postage, than trim the pane down to have a strip of 5 to mount.