Re-bucking rivets

I did a search on this forum, and on youtube etc, and ended up more confused. I have an old starcraft 14 foot aluminum with many leaking rivets. I want to eventually go the route of seam sealing with gluvit, but that is a project for later in the year when I have more time. I would like to try and rebuck some of the rivets that are leaking about halfway down the gunnels. Maybe it doesn't matter but I have seen and read two different ways to do this. One being to hold a bucking dolly/sledge/heavy piece of steel on the inside of the boat against the flattened tail of the rivet and then hit the rounded head on the outside of the boat with a hammer (no air tools for me). The confusing part is that I have read and seen videos where people do the opposite and hold the dolly against the rounded head on the outside of the boat and hit the flattened tail on the inside. I also seem to find people calling the rounded part the head, and calling the flattened part the head.

Thanks

if you can find just the head to an old sledge hammer,
take a 3/8 - 1/2 inch drill and drill a small indentation into the face of the hammer.
Then, that will "cup" the head of your rivet and protect it from becoming flattened.
in MY world, whatever works to get the rivet back to water tight works for me.
If you are a "purest" and want to maintain the round rivet look, then you need to
figure out how to make that "dimple" into your dolly the correct size for your rivets that will keep it rounded.
too deep of a dimple will distort the hull skin. Too shallow, will flatten the round head.
Pounding a rivet with two flat surfaces can only result in one thing - a flat rivet on both sides.
also, a long piece of 1" round or square steel stock about 2' long will give sufficient backing
to do the job. Just drill the dimple into the end of it. Also, it is easier to fit into tight spots.
Two people working together is the best.

and remember, you are not setting "new" rivets - you are just tightening up some loose ones.
so, it only takes a few gentle taps to get it done.

And, if you don't want to buck all those rivets, very neatly put a fingertip full of 3M-5200 Fast Cure
around each leaker on the inside of your boat - your call.