A true mashout is only needed if it is going to be an hour or two before you are able to boil your wort. Even then it really isn't necessary if you adjust your mash temperature a little higher to compensate.
A true mashout requires that you raise the grain bed temperature to at least 170° and hold it there for at least 20 - 25 minutes to actually denature the enzymes and stop further conversion. If you are batch sparging, you should be well on your way to a boil in that amount of time, so the mashout is just a waste of time. However, when doing a batch sparge, you do want to sparge with water in the 170° to 180° range as this will more efficiently rinse the sugars from the grains.
Don't be scared to go as high as 180° with your sparge water. Even that will not raise the temperature of the grain bed above 170°. You can get away with even hotter water than that. The so called problem of extracting tannins only shows up when you have the grain bed above 170° and your ph is above 7. When batch sparging, the ph almost never gets that high. You may approach that when doing a fly sparge. In fly sparging they say to stop sparging when the gravity of the runnings hits 1.010. The reason is not the gravity, per se, but the accompaning rise in ph. In batch sparging, in most cases you will not reach this level so it becomes pretty much a non - issue.
In short, don't stress over doing a mashout and extracting tannins. Just sparge with hot water and let it go. Good luck and have fun.
Wayne
Bugeater Brewing Company