Do you own an LV mallet? Let me know how you fare. I use my $10 GN mallet to knock my bats and they turn out fine. I stayed away from LV because of potential for damage to a bat. I could also get a (same weight) rubber mallet from HOme Depot for cheaper and it'd require the same amount of care and dexterity.
Having knocked in more than my fair share of bats, using both a cheap readers mallet and an LV mallet, I've never had an issue that I've damaged a bat knocking it in. As long as you don't start off by going at the willow like a bat out of hell you shouldn't experience any issues.
The LV mallet doesn't require so much force in the swing to create an indent in the willow, but due to the weight knocking in for a prolonged period isn't as easy on your arm as with a lighter mallet.
As for a rubber mallet, it may weigh the same but the LV mallet works so effectively because of the hardness and density of the material rather than the weight.