Hi Hama,
Regarding what is the optimum kill and picuk up radius, it depends on several things.
1) Do you have any +picukp radius in your gear?
2) Do you use ranged or melee classes?
3)A higher pickupradius and kill radius will slow your Xph by a fair amount. Choose your preference, faster leveling or pickup everything.
If it serves you, I use 20 kill range and 40 pickup range on my melee bots, and 50 kill range 80 pickup range in ranged ones. These options can also be tweaked on trinity-combat, where you can select to ignore any group of monsters with less than X monsters in Y radius. Try several and you'll find the one that suits you better.
When you change stats in Db, (like pickup radius and kill radius) you must realize profiles can, and usually do, change these settings. Look in every profile you are using for this line:
<ToggleTargeting questId="1" combat="True" looting="True" lootRadius="80" killRadius="45" />
values can be different and the commands itself may variate slightly. Change this accordingly to your preference in ALL the profiles you use. Not all profiles will have this line, but when they do, they override DB settings.
Thats it. Feel free to ask here or pm me if you have any doubt!