You'd be better off watering much less often, but watering longer when you do water. The goal is to provide about an inch of water each week, either from the sprinkling system or from rain, or a combination of the two. It's best to get it all at once, but since your lawn has been getting frequent water, you may need to change gradually because the grass probably has short roots now. Get some empty tuna cans and set them out around the lawn to see how much water you're providing, so that you'll know how to give the amount you need. The time the sprinklers need to run varies from one system to the next, and the only way to tell for sure is to measure the water that is being applied. I would cut back to three times a week (increasing the amount of time you water each station), then, after a couple of weeks there, cut back to twice a week, again increasing the amount of time for each station. After a few weeks at that, try to cut back to once a week, applying an inch when you water. If you have clay soil, you may need to do it in several cycles. I water for about 15 minutes per station, then let it sit a few minutes and do it again, then a few minutes after that, I do it third time. That way, the water has a chance to soak in and not run off.

Wow those are sunny warm conditions. Of outside you might be able to do it every other day. Really depends inthat mix. Unless anyone has better advice just do it enough to keep the soil moist to dry side of moist, not wet. Digg 2-3 inches down with ur finger to really tell. Te top might be bone dry but it could still be moist half way down where the roots are. If in doubt, go dry.

Datura usually doesn't need too much water. I water mine every couple of days, and that's probably excessive. You should be more careful with seedling, though, as they are quite fragile. Give them enough water to moisten the soil every three days, I say.

That having been said, for overseeding, you're going to have to water more often to get the seed to sprout. Seed that dries out is seed that dies. Regrettably, lawns that stay wet are lawns that get fungal diseases. You see the problem here. For seed, it will need to be watered about three times a day (even if under most coverings) to keep it appropriately damp. Underneath compost, that may be less often, but more water--depending on the compost, of course. Two would be the floor number. One is not going to be acceptable under most conditions, but there are certainly some exceptions. For how long that's required depends on the seed. In good conditions, rye usually sprouts in a week or so. Fescue, 10 days to 2 weeks. Kentucky bluegrass can be up to a month. Since you're talking about fall seeding, you've implied you have a transitional lawn and use northern grasses. Southern grasses will differ and are not generally fall sown. Of course, that can be even longer if the temperatures are particularly hot or particularly cold, and the clock also stops if the seed goes dry (this will also quickly kill germinating seed, as mentioned above). Post all that, cut back the watering slowly to let the new baby roots grow in, and let your adult lawn grow in roots it hasn't had to grow yet. Cut back to daily watering, then every other day in a week or so, every third day a week after that, and so on. See if it'll handle weekly watering the next year. Some lawns will, some won't. It does depend on your soil, the organic matter levels (OM hold water like nobody's business, it's like a sponge), and the lawn. I haven't watered since 2017 and mine looks good. Right now, we're 12 days with no rain and it's just starting to look dry in places, but my soil is tuned well for resources, the organic levels are kept very high, I keep it on the long side (short northern grasses are thirsty northern grasses), don't cut when it's dry (bleeding grass is grass that's losing water), and have bluegrass (one of the least drought-resistant grasses, actually, but it'll just go dormant if it does get droughty and come back when rains resume).