What angle should the blade be entering the water with?

If the paddle is horizontal the upper edge of the blade is forward of the lower edge (canted). That's one angle to consider.
The angle of the whole paddle to the water can be from what is called a low angle stroke 30 - 40 degrees to the horizon) to just about vertical.

The latter, near vertical, I'd use if in a hurry, the stroke you use when racing with a Wing paddle. Yes, there are videos of a "racing" stroke being used with a Greenland paddle.

If you use your body rotation and not your arms (bending your elbows to move the paddle) to put the power in, the paddle will move away from the hull. Not a great deal but a significant amount. If the paddle is taken to be vertical in the water (as an example), the blade edge away from the hull is forward of the blade edge nearest you. As the blade moves away from the hull it is acting like a wing with lift and the "lift" is in the direction you are moving. Adjusting that angle allows for the best "grip" on the water, the least slippage / wasted resistance.

Yes I bend my elbows to get the blade out of the water. Yes I do a low stroke at times, usually if I have to wait for others to catch up because doing the stroke efficiently means you go fast.

If you are hunting seals, a low stroke would be expected and probably with what is called a Storm paddle, so the seal would not be as likely to spot you. If the seals are on the shore and flighty, they'll spot you and go swimming whatever you do. If they are not flighty and in the water they sometimes clamber on board your kayak no matter what paddle you are using.