Here is an excerpt from “Greenland Paddles – The Basics”  (page 4) - regarding sizing of your Greenland Paddle. 

• What Size?

The first step in making a Greenland paddle is to calculate the paddle’s dimensions, which are based on your own dimensions. Note, however, that the traditional Greenland paddle is proportioned for the traditional Greenland kayak. Traditional proportions should work fine for similar-sized modern kayaks, but if you have a wide kayak (over 22 inches) or an unusually high fore-deck or seat, you might need to lengthen the paddle slightly. As you read the following descriptions, please refer to step 1 in Fig. 7.

• Overall length (L).

The overall length of the paddle should equal an arm span and the distance from the elbow to the wrist. For a slightly longer paddle, which was preferred by some Greenlanders for cruising, measure an arm span and a cubit (which is the distance from the elbow to the fingertips), or as high as the paddler can reach with the fingers hooked over the end of the paddle. For me, both methods yield 85 inches over-all for the longer paddle. None of the Greenland paddles I have seen documented exceed 82 inches, though paddles in Baffin Island could reach 110 inches. Note that the method of measuring a paddle by reaching up while standing is affected by the length of the paddler’s legs, which has nothing to do with his seated height.

• Length of the loom (S).

The length of the loom, or shaft, should be about the width of the shoulders or the span of the grip with the paddler’s elbows against the ribs and the forearms straight out. Normally, the thumbs and index fingers grasp the ends of the loom while the last three fingers grasp the roots of the blades, so your measurement using the second method should be from center finger to center finger. For me, both methods yield about 18 inches, though 20 inches seems to be fairly common among documented paddles. If in doubt, err on the short side. Then, if experience shows that the loom is too short, it can be lengthened by whittling away part of the blade roots—or you can use the sliding stroke.

• Thickness of the loom (T).

 In section, the loom is a rounded rectangle or oval with the long axis perpendicular to the plane of the blades. Make the long axis of the oval equal to the thickness of the two-by-four, which is about 1-1/2 inches. T is the other axis of the oval (the short axis). Heath suggests making it 1-1/8inches to 1-1/4 inches, though 1 inch by 1-1/2 inches seems most common among the documented traditional paddles. If in doubt, use the larger figure, since you can always reduce it later. The resulting loom should fit into the oval formed by touching the tip of your fore finger to the ball of your thumb.

• Width of the blades (W).

 Make a wide C with your index finger and thumb. To use the paddle in the extended position, the maximum width of the blades should be no more than you can grasp comfortably between the second joint of the index finger and the web of the thumb. For me that is about 3-3/8 inches. Few authentic blades exceeded 3 inches and many were less. The blades taper to half the maximum width at the blade roots.

Here is a basic reference regarding length:

5′-1″ and under                      79
5’-1” to 5’-3”                            81
5’-3” to 5’-5”                            83
5’-6” to 5’-8”                            85
5’-9 ” to 5’-11”                         87
6’-0   to 6’-2”                           89
6’- 3”  and  above                   91