Welcome to the router forums Bluegoose nice to have you here. As for the questions I will try to answer:
What drawer side do I cut facing up and what drawer side do I cut facing down?
EZlink uses a straight bit so it doen't matter which side is facing up having said that there is a need to have the drawer front and two side matching. So if we cut the drawer front with drawer bottom tight to the pin on both ends then we need to have the sides with the bottom tight to the pins to match. Try this with some scrap pieces first to understand how the jig works.
Is there a formula to show you how much to allow for the dovetail measurements? The tongue and pocket of the EZlink is 3/8". The length of the drawer is determined by the size of cabinet, type of drawer front and length of drawer hardware. 16", 20", 24" are standard lengths for drawer hardware. Example: If your using the 1/2" false front and you have 16" drawer hardware you take 1/2(drawer front) - 3/8"(tongue/pocket) = 1/8" what's left over. 1/8" - 16" = 15 7/8" length of side for drawer. Height is determined by the position of drawer bottom to fit the drawer hardware. Usually the hardware needs 1/2" clearance. Each hardware is different so you need to check with your hardware manufacture. The width of the drawer is not affected by the joint unless you measure from the inside of the drawer. This is usually not really important so just make the length of the drawer front to match the recommended clearance of the drawer hardware.
To get the width of your drawer bottom and length of the drawer back we determine the depth of groove and dado to be 1/2 the material thickness of the side. The EZ link joint cuts the full material thickness so this means 2 material thicknesses smaller for the EZlink joint and add 1 material thickness for the depth of the groove and dado. This leaves the length of the drawer back and width of the drawer bottom to be one side material thickness smaller than the overall length of the drawer front.
Hopefully this answers your questions.
What drawer side do I cut facing up and what drawer side do I cut facing down?
EZlink uses a straight bit so it doen't matter which side is facing up having said that there is a need to have the drawer front and two side matching. So if we cut the drawer front with drawer bottom tight to the pin on both ends then we need to have the sides with the bottom tight to the pins to match. Try this with some scrap pieces first to understand how the jig works.
Is there a formula to show you how much to allow for the dovetail measurements? The tongue and pocket of the EZlink is 3/8". The length of the drawer is determined by the size of cabinet, type of drawer front and length of drawer hardware. 16", 20", 24" are standard lengths for drawer hardware. Example: If your using the 1/2" false front and you have 16" drawer hardware you take 1/2(drawer front) - 3/8"(tongue/pocket) = 1/8" what's left over. 1/8" - 16" = 15 7/8" length of side for drawer. Height is determined by the position of drawer bottom to fit the drawer hardware. Usually the hardware needs 1/2" clearance. Each hardware is different so you need to check with your hardware manufacture. The width of the drawer is not affected by the joint unless you measure from the inside of the drawer. This is usually not really important so just make the length of the drawer front to match the recommended clearance of the drawer hardware.
To get the width of your drawer bottom and length of the drawer back we determine the depth of groove and dado to be 1/2 the material thickness of the side. The EZ link joint cuts the full material thickness so this means 2 material thicknesses smaller for the EZlink joint and add 1 material thickness for the depth of the groove and dado. This leaves the length of the drawer back and width of the drawer bottom to be one side material thickness smaller than the overall length of the drawer front.
Hopefully this answers your questions.
