I have a similar problem and need to make changes to the display if a userfield value is set.

I am pretty sure $bbuserinfo refers to the logged in user, while $postinfo refers to the person who made the post. So you would want to use a value in $postinfo in your case. I did not think that the names of the fields were available at this level, so I am using $bbuserinfo[field11] to refer to my field in the template. That seems to work just fine and I can control the display with that value with <if condition="$bbuserinfo[field11]> stuff </if> at the appropriate place in the template.

My problem is that I cannot figure out how to set the value in the database at my hook location. I could generate the sql, but I thought I should use the user datamanager to do that and I cannot find either examples or documentation on how to set a userfield programmatically. Setting it directly with a query seems like a coding standard violation.

btw, I would have thought you could just use ratings for the ovenmitts and change the rating symbol. Here is what we did for a similar donor display with the donor having the option to not display the symbol.