Well, as a newbie Hung Gar practitioner I can't say much. As someone who has done various martial arts for a little over twenty years, here are my findings:
I have a rather heavy bag hanging in my garage, and it's not filled with feathers and cotton. Before I started training with the boys I used plain bicycle gloves, simply because the bag has a lot in common with sandpaper and I didn't want to skin my knuckles off. Then I got 8oz fingerless grappling gloves, and was able to really hammer the bag far more than 'gloveless' without any aching, and that was hitting straight on, proper tight fist.
Here is my advice, and you can do what you want with it: Hit the bag solid without gloves, to feel the difference. I advice you to work up the power, don't just blast into it first go, if your structure is wrong you WILL hurt yourself. Turn up the volume from light to hard. Once you feel the correct structure and body movement, then you can put on some gloves and drill and whatnot. I tell the boys to 'bury the fist' that is, aim fist deep in the target. Too far away and you either tap or over extend your structure, leaning, locking the arm, in short you aren't in the 'zone'. Too close and it turns more into a high speed push or shove.
Also, you can put your fist to the wall, whatever knuckles you strike with and lean on it. Adjust your arm, the angle of the elbow etc until you can hold it without burning muscle, that is, where your structure supports it.
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As for the glove vs no-glove, here is an interesting article about how sports fighting has changed over the years:
http://www.nononsenseselfdefense.com/evolution.html
Hope this helps.
V.
Here's to cheating, stealing, fighting, and drinking.
If you cheat, may you cheat death.
If you steal, may you steal a woman's heart.
If you fight, may you fight for a brother.
And if you drink, may you drink with me.