Mark, I have used the kevlar sleeve approach in the past. I don't know if it is more visible but it plays on my mind!!
Brandon,
I also use the nail and think it's the only alternative to crimps. I tend to leave generous tags, too. Will try Peter's, but when I've got some time.
One the note of the visibility of the kevlar - I guess that's also relative to the fish's temperament. More often than not, the GT bite is reactionary and territorial (although there slow times definitely stick out significantly where you really need to work on shy and timid GTs!)...
I noted that Fukui-San uses Kevlar on ALL his GT rigs and obviously catches GT left right and centre. The first time I saw this he sunk a Pandora 155 with Kevlar some 60 metres down and a few metres later had hooked up and passed on a 50kg GT to one of his clients.
Unless the bite becomes really slow and hard-work, I guess that's why we have many rod configurations to switch, swap and change - if in doubt, simply go back to standard nylon, feel comfortable in your confidence - guess it's better to hook-up and risk it, than not to hook at all, right?