I have yet to try one of those broken snaffles with the roller (ala billy allen), however we are currently riding everybody in tom thumbs right now. Regular snaffles just don't have any whoah (all our horses are at least 8), and nobody truly likes the curbs i've got (old aluminum ones).
I also have to disagree that tom thumbs are "harsh." as has been said here thousands of times, ANY bit in the wrong hands can easily be harsh. TT's can also be one of the mildest bits.
Anyhow, in answer, try her in it. It certainly can't hurt anything as TT's aren't very expensive.
Oh, and I have zero problems plow/direct reigning my wife's TB in a tom thumb, and neither does she....
Last edited by spence; 08-04-2010 at 11:01 PM.