I use those braided mono loops for 6 wt & under trout rods. etc... they work great for that type of work in my humble opinion. I use a nail knot with some fine Mono thread to secure the end instead of the heat shrink tubing stuff the send with the kits.
As far as the mono loop. If you have a leader tied onto your fly line & it is beyond repair. cut off all bit the last six inches or so & tie a surgeons loop or a perfection loop in the end and then use that loop as you loop to loop connection. I have a few lines that that has been done.
Or tie one of Juro's loop connections. http://www.flyfishingforum.com/flyta...ad.php?t=21921