I just bought some leadcore for the first time about a fortnight ago and i was worried about splicing my own too as i didnt feel the spliced section would be strong enough, so i made some up in work looped around some metal pegs and tugged and hanged on the leadcore. It did break eventually only after some severe punishment but it snapped about an inch from the spliced section and after that little field test im 100% confident in it now.