I recently bought the 13 Overrun Countries plate blocks (Scott #s US 909-921). They are blocks of six. To mount them in Showgard 240/63 mounts, I will need twice the number of mounts than I would need if they were blocks of four. The mounts aren't cheap. Do I tear off two stamps from each block, or should I bite the bullet and buy the extra mounts? The stamps are in excellent condition.
Definitely keep them as blocks of 6. If they are top margin blocks with guide markings, the catalog values increase by about $2 for those extra two stamps that would otherwise have a catalog value of only 25 cents if separated from the multiple.
If oversized mounts are cost prohibitive, you can always consider using stockbook pages or page protectors or some other means to display these stamps. There are no rules for the proper way to display your stamps. The only one you have to please is yourself, as it's your collection and you should do what suits you best.
Like wt1 said, it's your collection, do it your way.
Everyone else does...
A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed. (The exact & entire wording of the 2nd Amendment to the U.S. Constitution)
I agree 99.999999999999 percent of the time stamps and other philathetic material should be kept as found. I was at a big antique show in Bloomington Illinois and came across a dealer of antigue stationary. She had an envelope and entire letter from the very early 1800s that was to the Queen of England. The envelope had part of the corner neatly cut off and had a faint smudge at the point of the seal. When asked about it she said the wax seal was a bit cracked so she scraped it off and as for the corner of the envelope it was a bit smeared she said, so I cut it off. Some just don't know, even some that are expert..... Aaarrrgggghhhhh!