There are lots of thoughts on grass clipping as mulch expressed in this
thread and I've seen people do most of them.
If you put down your clippings as mulch, it will build over time and while it can help retain water in the soil it can also create a suffocating item called thatch which will kill the grass plants.
If you bag your clippings and add them to your compost heap, they will induce heating of the compost pile, always a good thing.
Mulch can be spread over grass and watered in, this replenishes the soil with the nutrients the grass plants need while not creating the thatch scenario (win - win situation).
Sprinkling has been shown to put about 1.4 of the water applied into the atmosphere, without ever getting down into the soil, leaky hose, buried 2" under the surface of the soil allows easy watering with no evaporation.
If you must use sprinklers, then early morning (just before sunrise) is the preferred time, this gets most of the water into the soil and does not create situations where the grass plants are wet long
enough to have molds form. (dew normally doesn't make it down into the soil and is gone just a few hours after the sun comes up in most cases).
Lawns
should be watered for at least one hour, once a week (twice a week in really hot weather) less just makes the
roots grow so shallow that the lawn will not survive really hot weather without daily watering.
Grass plants do best when cut to a height of between 1.5 and 3 inches in length, shorter when colder, longer when the heat is on is a good rule of thumb for mowing. When the grass has grown above 5" in height, don't cut more than two inches off, better to cut twice a week to get it back down to proper height.
Grass shoots lengthen the stalk (part that the green blades come from), so if you cut so short that only these stalks are left, the grass plants can die off, then the grass becomes thinner in density allowing weed seed the light they need to sprout.
Over seeding is the best method for choking out weeds. When I worked at a Nursery putting in new lawns we would seed and when the plants were up two weeks we would mow and seed again, once those plants were up for two weeks we came back, mowed and seeded again, this builds a thick lawn that has so many grass plants that weeds have a very hard time getting established. (This is also the method used by the best sod farms for the grass they
sell).
On Buzzard's Roost, we have an area of lawn for recreation time, it has been over seeded four times and is more like a carpet under bare feet.
Your soil profile is ok. Your grass will not be harmed by removing the clippings, deep watering and over seeding will in fact
boost the breakup of the underlying clay. If you notice browning problems a shot of Ag Lime using a drop spreader on a small number setting will help things along.
The best method of using clippings as fertilizer is to mulch mow every five mowings this prevents your mulch getting to the thatch point. It does not hurt a lawn to have all clippings bagged and removed to the compost heap.