1. use different line and tie the hair rig as normal, once done, cut and leave about 1" tag. Get a lighter and burn the tag back to the eye leaving a blob (stronger than any knott) then get your main line and tie the hook on as you would normally. Classed as fishing completely straight through.
2. use a completly different hook link. 12lb main line and a 10lb hook link (for example). Tie the hair as normal then leave yourself about 14" then tie the swivel to the other end of it and should leave you about 10/12" hook link (perfect / average length) tie another swivel to your main line and use a quick link (ESP) and attach to 2 together
I tie the hair first using of one those green loop tyer things. Cut the line to the length I want. Tie the hook onto the hook length. Tie a loop in the other end of the hook length and then use the loop to loop method to put the hook length onto the main line.
if you have any fake corn (i 100% advise you to get some) when you tie your hair loop on the line (slide the hook on 1st [:T] ) attach the amount of corn you want to use with a hair stop, as normal then position the hook where you want it (length of hair is your choice) and then tie the knottless knott 
I tie mine on to a length of hooklength line using a sliding knot then tie the hair using the knotless knot. Hook onto a pin in a piece of board and tie the loop at the right length marked on the board. I usually start with about 5 foot of hooklength line and get 4 ten inch hooklengths out of it.