What knot do you find to be the best for least amount of line strength loss when tied?

In my low tech tests I have tied blood, surgeons, and a multitude of others and they all seem to cut my tippet strength in half always breaking at the knot.

It seems that when the same knots tied in higher lb test leaders to tippet the ratio of strength increases % wise.

Example: 4X = fails at .5% rated, 12lb = fails at.75% rated.

Because of this I tend to not add tippet to leaders 3X and smaller but just resort to cutting them to about 5' and tying on a 12 to 14lb mono and using them for Bass and larger saltwater fish.

Just trying to get a little longer life out of my smaller lb test leaders especially when changing flies a lot.

Thanks,
Leo C