進退これ谷まる	21
進退維谷まる	0
進退これ谷	0
進退維谷	0

We wouldn't remove an entry which is in Daijisen unless it was found nowhere in use. This just makes it.
I doubt 進退維谷 is worth an entry.

進退これ谷まる	21	100.0%
進退維谷まる	0	0.0%
進退これきわまる	0	0.0%
進退維きわまる	0	0.0%
進退これ極まる	0	0.0%
進退維極まる	0	0.0%
進退これ窮まる	0	0.0%
進退維窮まる	0	0.0%

進退これ谷まって	0	0.0%
進退維谷まって	0	0.0%
進退これきわまって	0	0.0%
進退維きわまって	0	0.0%
進退これ極まって	0	0.0%
進退維極まって	0	0.0%
進退これ窮まって	0	0.0%
進退維窮まって	0	0.0%

進退これ谷まった	0	0.0%
進退維谷まった	0	0.0%
進退これきわまった	0	0.0%
進退維きわまった	0	0.0%
進退これ極まった	0	0.0%
進退維極まった	0	0.0%
進退これ窮まった	0	0.0%
進退維窮まった	0	0.0%

This entry seems absurdly rare, but in daijs, so feel free to discard this suggestion with little/no remarks. (I will understand the meaning :)

Instead of an xref, would it be possible to just *add* 進退これ谷まる and 進退維谷まる as [sK] in 進退窮まる?  They are entered as exact synonyms anyway.  Then if you search for this term you'll get the right answer, at least. No one is going to learn this form from this dictionary and then try to apply it. (or, at least they shouldn't).  

Then, if desired, we could [sK] the 谷まる forms without leaving an inconsistency.  (or leave them [rK], which I am still fine with).

(Also, note: There is a far-more popular 4-character compound which we don't carry, same kanji, same meaning: しんたいいこく【進退維谷】.  It's *extremely* common-looking in Chinese news sources, but not actually so much in Japanese, so I haven't made an effort to add it.  Appears in 四字熟語辞典)

Aligning.

@@ -16 +16 @@
-<xref type="see" seq="1884050">進退窮まる・しんたいきわまる・1</xref>
+<xref type="see" seq="1884050">進退窮まる・1</xref>
@@ -18,2 +18,3 @@
-<gloss>to be at a loss</gloss>
-<gloss>to be in a corner</gloss>
+<gloss>to be driven into a corner</gloss>
+<gloss>to be left with nowhere to turn</gloss>
+<gloss>to be in a dilemma</gloss>

@@ -16,0 +17 @@
+<misc>&obsc;</misc>

進退維谷まる	No matches
進退これ谷まる	21
daijr, daijs: https://kotobank.jp/word/進退維谷まる-538273
nikk: https://kotobank.jp/word/進退これ谷まる-2052219