I am about 5 all-grain brews in so I am newbie myself with the all-grain. I’ll just give you some info I find helpful.
For mash volume, it is recommended to use either 1.25quarts or 1.5 quarts per 1lb of grain for your mash (you will determine which volume you like the more you do this.) If using 10lbs of grain, you would use 3.33gals of water at 152F (using your example and the website below). However, because of how my mash tun is set up, I add an extra gallon to my mash by taking it away from my sparge volume to account for my false bottom and filter I place in the mash tun. So my total mash vol would be 4.33gals.
How to determine how much total water is different because you will lose water to your equipment, to grain absorption, trub loss, wort shrinkage, etc… All of this needs to be taken into consideration during the mash process because this is where all of your measurements need to be right on target. As the other brewers suggested, use http://www.brew365.com/mash_sparge_water_calculator.php . I find it even better than BeerSmith because there aren’t so many variables (user error is at a minimum). When I use this, my numbers come out almost perfect (knock on wood).
If this were my brew, I would have approx 4.33 gals of water at 152F for my mash. After one hour, I drain it slowly…ssslllloooowwwwwllllyyyy. Begin heating additional water in separate pot to a strike temp of 170F. Once wort is completely drained and strike water is at 170F, poor into mash tun. Stir to redistribute grains and expose to newly added water (this is batch sparging). Place top on mash tun, let sit for 10mins. Then drain slowly to remove all remaining residual sugars. Test your pre-boil gravity, once you find out the gravity there are conversion charts online that will give you an approximation of what the post-boil/OG will be. This will allow you to determine if you have the right pre-boil gravity for your beer or if you should add some DME. Knowing these numbers will reveal a lot of info about your process and its efficiency.
Your sparge volume should be enough water to bring your ‘mash out’ volume to approx 6gals for a 5 gal brew based on a “1gal/per hour of boil” evaporation rate. If you have a pot that is measured in quarts/gallons, perfect. If not, try to mark/guesstimate on your pot where 6gals, 7gals, 8gals, etc… are so you know your wort and water levels. During the mash out process you will collect approx 2.03gals of wort depending on your grain absorption and equipment loss. So your sparge volume should be roughly 4.34gals to get you to approx 6gals (remember that I took one gal away from the sparge to add to my mash). All of this is based on the info I inputted into the link I provided above.
If you find your mash tun is below temp, put the top on tight and quickly boil a 1/2gal – 1 gal of water to the mash temp and poor it in. It will bring the temp up to where you need it.
In the beginning, I would stick with batch sparging. I have found it easier and it always gets my numbers right on target.
Let me be very clear, all of this information is specific to my process. In the all-grain world, your all-grain brewing set-up is like your own baby, it will be different from everyone else’s. You may experience more or less equipment loss, grain absorption, etc… for various reasons. You can use this as a guideline, but not as gospel. For example, on every brew I collect 7gals of wort and I end up with just over 5gals for bottling. My evaporation rate appears higher than some. This is just some of the stuff you learn. In the example I provided above, you may not need to add more water to your mash step by taking it away from your sparge step like I did. Again, it’s specific to your own brewery process.
I hope this helps. It ran a little longer than I wanted, but I tried to pack all the info in you needed.