Singular or plural reference to people on a panel,bench, commission etc

When referring to a number of people on a panel, bench or commission, is it correct to refer to the people on such panel/bench/commission in the singular or plural?

Eg.

The 3-judge panel decided the case

or

The 3-judges panel decided the case

If expanded, then the correct usage would certainly be: "The panel of 3 judges decided something" but is the same, plural reference true for the shortened form?

Solution 1:

In hyphenated phrases of measure or count, the noun or measurement being counted is always singular. A three-judge panel, a five-mile walk, a six-metre drop, a two-room apartment, but a panel of three judges, a walk of five miles, a drop of six metres, an apartment of two rooms. Note: it is usual to write small numbers (less than 11) as words.

Solution 2:

Three-judge, five-star, ten-pound, etc. are compound adjectives in such phrases as three-judge panel, five-star hotel, ten-pound note, etc.

Adjectives don't have plural forms like nouns.

Three judges, five stars, ten pounds, etc. are phrases. They consist of the cardinal numeral and the noun.

Nouns can have plural forms when they are modified by numerals.