the 1/8-1/4" you are referring to is called drawback and that is a normal amount that you are experiencing. you will notice as you pull the next string most of the drawback of the previous string is taken so you don't really lose much if anything. as long as the amount is consistant from string to string and is not excessive you are good.
as far as the ratcheting gripper goes...... start with the arm down (not up) wrap the string around the drum and thru the slot, give the drum a twist so that it clicks a couple times to lock down on the string, hold the drum with your left hand and lift the bar with your right hand. if the drum is in a position where it is awkward to wrap the string around it and thread the slot just rotate it by hand to a position that is more suitable to your technique. there is nothing wrong or abnormal about it and it won't harm your machine....
you will also see that as you get to the end of the string job if the string is very short, how you have the drum positioned to thread the last string for the last pull can be critical. if you have the drum in the wrong position you won't be able to thread the string thru the slot and get the jaws to lock down on it....so like i said above...everything you have described is quite normal, have fun and you will learn how to string more efficiently with your new machine the more you use it.