Earth-Sol L1 is probably a bad place for a solar shade. That's where a solar shade of any given size is the most efficient, but the cost of getting it there is much more than the cost of having more, less efficient ones.
A better choice is something akin to a semi-sun-synchronous Molniya-style-orbit. That is, orbit that is somewhat highly elliptical (so a satellite on it spends most of it's time near apogee, and zips through the perigee relatively quickly), and which precesses so that the apogee is always between the earth and the sun.
A satellite on such an orbit can easily spend >70% of it's time between the earth and the sun, and you could send many satellites there for a similar cost to putting just one to Earth-Sun L1.
