岩	4,239,688	86.6%	
巌	334,371	        6.8%	
磐	268,423	        5.5%	
巖	52,145	        1.1%  - oK -> sK

I don't think "cliff" is right. The JEs don't have it.
The anchor sense is archaic. I don't think it's needed. Daijr and koj have it as a separate entry with different kanji.

@@ -18 +18 @@
-<ke_inf>&oK;</ke_inf>
+<ke_inf>&sK;</ke_inf>
@@ -34,5 +33,0 @@
-<gloss>cliff</gloss>
-</sense>
-<sense>
-<pos>&n;</pos>
-<gloss>anchor</gloss>

I agree. I have proposed an iwao entry.

@@ -26,5 +26,0 @@
-<r_ele>
-<reb>いわお</reb>
-<re_restr>巌</re_restr>
-<re_restr>巖</re_restr>
-</r_ele>
@@ -42,1 +37,0 @@
-<stagr>いわ</stagr>

realized there's already an iwa entry for the fishing net, 
though it didn't include 岩

@@ -46,5 +46,0 @@
-<sense>
-<stagr>いわ</stagr>
-<pos>&n;</pos>
-<gloss>fishing net weight</gloss>
-</sense>

daij, jwn
not sure いわお applies to sense 1

prog splits out いわお【巌】 as "a great [massive] rock"
daijs and nikk also single it out as "高く大きな岩。" "大きな岩"
I think it should be split out

@@ -34,0 +34,4 @@
+<gloss>boulder</gloss>
+</sense>
+<sense>
+<pos>&n;</pos>
@@ -35,0 +39,11 @@
+<gloss>cliff</gloss>
+</sense>
+<sense>
+<stagr>いわ</stagr>
+<pos>&n;</pos>
+<gloss>anchor</gloss>
+</sense>
+<sense>
+<stagr>いわ</stagr>
+<pos>&n;</pos>
+<gloss>fishing net weight</gloss>