Can a 21x21 realistically accommodate these themers?

[Aw7777]

Hi everyone! I'm new to this and had a construction question. I know I can search for grid possibilities for 15x15 puzzles. Is there a similar resource for 21x21s? I ask because I have a theme in mind with some very long themers and I'm honestly not sure if it's even possible.

My themers are 21, 21, 21, 20, and 18. Is there a chance of fitting those in a grid? Thank you!

[mmcbs]

Not if you want to conform to the standard symmetry of the grid, which editors generally require. Your themers need to come in pairs (2 of whatever length) plus you can have one odd-numbered themer in the very center of the grid.  If you can come up with another 18 or 20 then you would have a viable theme set. However, some editors prefer at least six themers, but it's not an absolute rule.

[Aw7777]

Thank you! I appreciate it. I'll see what I can come up with.

[Kem Balani]

July 06, 2021
Mr. or Ms. "Newbie"
Of course you can, Mr. or Ms. "Newbie", just as Mark McClain so expertly replied to your query.

This work of mine shows you 3 out of 5 theme entries having 21 letters:                                           
https://www.cruciverb.com/data.php?op=showpuzzle&puzzle_id=7956
If I had 5 (or more maybe) 21-letter entries, I probably could have done that as well!

And let me add that Mark McClain is a VERY helpful guy !
Kumar (Kem) Balani