Both my buddy and I use light charges in our BIG English rifles, mine a .69 and his a .75. They smash snowshoes rabbits heads quite well. As far as 1/2 measure, etc, a 1/2 measure for me would have been 3 drams 2F and that would be too much for small game, but perfect for the trail walk on steel targets to 100yds.
: My powder chargers carry 3 drams and 6 drams, however my smallgame chargeron a Dixon flask holds between 2 1/2drams 2F, but I only fill it about 1/2 way. I've tried barking squirrels, and it may work on eastern squirels but it doesn't work well on the pine squirels up here. When a full hunting charge in the barrel, I'm not hunting small game, however did try to bark a scolding, chattering red squirrels twice, and did hit the bark about perfectly on a big spruce tree, but the blast sent the first small squirrel flying off into the bush and I couldn't find it. The other shot, perhaps a bit close, blasted the squirrel apart from the bark explosion. I found 2 large pieces of that one. So much for barking- leave it to the dogs - they're better at it. I suppose barking a large black, grey or fox squirrel might be fun and a .45 on up to .54 should do it, but the large bores will make more bark fly.