Jurors aren't paid: they get travel (not much, by definition they're local) and subsistence (again, not much — a pub lunch per day each, at most). Selecting jurors is just a lottery system, so very easily automated. Deal with jurors being objected to, or pleading excuses, can be dealt with by the automated system in advance.
No-shows on the day can be dealt with by inviting a percentage of extra jurors.
/Continued