How do I update a specific object in an array, in user meta?

Question

I have this array, below, to set custom user meta (lh_userbadges) in user_meta but I'm not exactly sure how to update just parts of the array later on...

$lh_user_badges = array(
    'lh_userbadge_comments25' => '0',
    'lh_userbadge_comments50' => '0',
    'lh_userbadge_comments75' => '0',
    'lh_userbadge_comments100' => '0',
    'lh_userbadge_comments150' => '0',
    'lh_userbadge_submited' => '0',
    //etc.
);
update_user_meta($user_id, 'lh_userbadges', $lh_user_badges);

From what I gathered in other stack overflow questions (How to update serialized data in the user meta data is a good example BUT it just increments, which I don't want. I want to set a specific number just once.), I think it something along these lines but, I'm just not sure....

$meta_value = get_user_meta($user_id, 'lh_userbadges', false);
$meta_value['lh_userbadge_comments25']  //....?

So, for example, I just want to update the object lh_userbadge_comments25 from lh_userbadges from 0 to (lets say) 25, how would I do that? I think I'm on the right track with that 2nd part of code but I do not know...

Any ideas? Also, I'm not sure if this is the best way to do it but I figured this would save database clutter if I did it in this format rather than each type being it's own meta item.