I think this is worth having to pin down the ...びゃっこ.

@@ -12,2 +12,1 @@
-<gloss>how many hundreds</gloss>
-<gloss>a large number</gloss>
+<gloss>large number of items</gloss>

Simply a + b, but the reading is the plague for the novice.

Obviously it gets many Google hits, but is "個" to be read as "か" or "こ"?　Your main entry for "何百" gives the help on "百" being "びゃく" and not "ひゃく", but again this entry itself is only a + b.

How far should one go? It understsnd that it is difficult. Sometimes I wonder if there is a case for expanding the entry for numbers to show the obvious counters, etc., with the main entry. Obviously you cannot have a separate entry for "何" in front of all applicable cases, nor a separate entry for counters attached to numbers. However, maybe one could have the brief addition to the main entry for say  "百" which would solve the issue for questions and counters.