Many farmers have had trouble getting a good stand of legumes when using Clinton or "Clinton-like" oats as a companion crop. There are some reasons why these oat varieties must be handled a little differently. But they still make a good companion crop if they aren't seeded too thick.
Dyas, E. S.
"Seeding Rates for Oats,"
Iowa Farm Science: Vol. 2
, Article 4.
Available at: https://lib.dr.iastate.edu/farmscience/vol2/iss9/4