even if u wanna make the link seal, try doing it with a petition letter spell to make sure of make the seal be effective, cuz there can be some problems like the link became share with the binded and he also can take control of the link, or that the seal became share between the bloodline of the binded with the caster, and it became a generational curse, also to ensure that the binded dont relationated the caster when the seal became activated. the petition letter link is here.
also take advantage of the summer solstice to make more stronger the spell, the best day is june 24th , also known as st. John eve, in case that u wanna make another spell than the letter spell.