Suspension questions

[leon205gti]

Hi there, i have 2 big questions that looks for answer...

Fisrt, i've converted my front legs to coilover, and since that i ve been running with wrong springs looking for the best rate. On different places i realised it should be arround 7kg front and 5kg rear. Now im readdy to order the springs but i dont know what is the equivalent rate of 7kg to X pounds/ins that its what you have to select on demontweeks.
Also, where can i get the 5kg rear springs?

And second, i have bilstein inserts on front. It works as upsidendown damper so the main rod is on the bottom of the insert. Can i make a bigger hole on the bottom of the insert and on the bottom of the leg so the rod can pass through them and i can get a little more travel on the damper without riseing the car?

Thanks a lot in advance