That looks like a Dive Curve for #40 Tru-Trips.... Luhr Jensen Jet Divers run a much lower Curve....meaning it takes a lot more line. Type of line does figure in slightly...Here's the Dive Curves for both if using 30# PowerPro:

Code:
#40 Tru-Trip		#40 Jet Diver (Top Hole)	
30# PowerPro		30# PowerPro	
Depth	Line Out	Depth	Line Out	
8      	15     		8		
10     	20    		10     	28	
12     	22    		12     	36	
14     	25     		14     	43
15     	25     		15	
16     	30    		16     	50
17.5   	35    		17	
18            		18     	60
20      42     	        20     	70	
22    	50     		22     	80	
24     	58     		24    	90	
26    	65	        26    	105	
28     	70    		28    	118	
30    	75    		30    	134
32     	80     		32    	150	
34            		34    	170
35     	88	        35	
36     	92     		36    	190	
38    	105    		38		
40     	125    		40
Speed can affect the depth, higher speeds will give you deeper dive, but these are very consistent in the dive curve from 1.5 to 2.5... Smaller line will give you greater depth, larger diameter will give you less depth, but only by a small percentage.

If you're pulling big boards, there is a slight rise in your tow line from the board to the boat. That itself will account for a couple foot of change in the water column. If you're marking fish at 20 feet, I would set my first line at 18-22 back, that's checking for high fish you might not see, or fish that want to come up to hit baits, usually in cleaner water. All others lines I'd set at 35-40-45, then see what hits. If all your fish start coming at 35 and 40, reset your other leads to that. Try a 37 or 38, splitting the difference...

Couple key things to remember: BIG difference in dive curve from a #40 TT to a #40 JetDiver... also, pull baits above the walleye. Suspended walleye won't usually go down to get a bait, they feed up. Bottom walleyes can be different.... they'll pick a bait off the bottom, but we're not usually trolling for bottom dwellers!

So, once you figure out the depth they want, then the color and type bait, along with the speed, then match it up with their preferred direction - you'll be whackin' em! Experiment a little each day, and pay close attention to what leads are catching.... after the first few fish, hopefully a pattern will start to develop.

Good luck!