Well, I guess I'm going to answer my own question. I had already put the soaker hose on before typing the above. I would normally assume that the hose wasn't needed the day after a good rain. However, a couple hours of additional soaking seems to have brought them almost completely back. I guess I will just have to keep the system running very slowly if I can control it.

I would not try to use the wilting as a reason to control when to water. This can make you water too much and... roots that find themselves in wet soil can develop root rot. If the roots get root rot, the plant will look wilted 24/7 so be careful. Good drainage in the soil can help minimize the chances of getting root rot.

When you water the shrub, do so early (6am ish) and water the soil only from the root ball outwards. Try to make sure that water reaches down to a depth of 8" with each watering. How much water you end up giving the shrub will vary based on the size of the shrub and the the amount of roots but use 1 gallon per plant per watering as a start and tweak until you get coverage to about 8" deep. Remember to increase the amount of water as summer arrives and to decrease back to Spring levels as summer temperatures moderate. Also, make sure that you have 2-4" of organic mulch up to the drip line or more.

Wilting occurs when the plants' leaves loose moisture faster than the roots can absorb water. Heat above 85F, high winds or hot winds can make wilting episodes occur. Notice I did not say anything about having received rainfall.Give them rain in the morning and hot sun & winds in the afternoon and you can have some of the shrubs wilting. And others holding on just fine. The ones that loose moisture faster than they absorb water will wilt.

Shrubs located beside each other are not the same shrubs. They have different number of leaves, blooms, they may get different amounts of sunlight and have different size root systems. So one wilts and the next one may not wilt.

If a plant is wilted but the soil is not dry, it should fix itself at night and appear fine in the morning. You do not need to do anything to such a shrub. If you see an extreme wilting episode, immediately give the shrub 1g of water from the root ball outwards. Water the soil; never the leaves. If the wilting is not an extreme wilting episode then check to see if the soil feels dry or not. If dry then water the soil; if the soil is moist or wet, leave it alone.

Temps and or winds may cause wilting. Make sure the shrub does not get late afternoon or evening sun. See if there are tree roots competing for water or see if the soil is sandy. Sandy soil can require 50% more soil than usual. See if the location is windy too.

If application of water via the soaker hose does not help, it was not enough water or the roots are in too much water and the shrub is starving for oxygen. The roots could also start to get root rot. So again, please be careful not to over do the watering.

I normally water if a finger inserted into the soil to a depth of 4" feels dry or almost dry. Or you can also use a moisture meter.