New to AG. Couple of questions

So homebrewing has completely consumed my life now and im ready to move on to AG brewing. All i have right now are some buckets and a 4 gallon brew pot. Ive done a lot of research and below is what i have found as the most economical way to get into AG. Is this a good set up?

http://www.homebrewstuff.com/servlet/the-284/8-gallon-32-qt/Detail

http://www.homebrewstuff.com/servlet/the-57/15-gallon-60-qt/Detail

http://www.homebrewstuff.com/servlet/the-277/Copper-immersion-wort-chiller/Detail

I am currently just going to be making 5 gallon batches and i already have a propane burner. From what i understand when doing a full boil i would want to start with 6-6.5 gallons of water and boil it down to 5. Is this right? So how much water would i mash with and then sparge to get to 6 gallons? Would a 7.5 gallon pot be big enough to boil 6-6.5 gallons? Also would i be able to do multiple mash temperatures with this set up? I've done a lot of reading (both books and on HBT) but im still a little confused on the whole mashing and sparging process so any other pointers would be greatly appreciated. Thanks

If you want to start with just 5 gallons at a time 8 gallon pot is ideal,however you may find that if it is consuming your life now, you WILL move to 10 gallon batches, might want to get a 15 gallon pot now for the 10 gallon move that wil happen soon.(just saying) as far as mashing and sparging,the amount of water needed depends on the water to grist ratio,I usually stick to 1.2 qts per lb. software programs like beersmith,promash,brewtarget ,etc can help calculate all of this stuff...you tell it how many lbs of grain in your bill and it tells you how much water(liquor) is needed for said mash.i usually sparge(fly) till i get to my desired pre boil volume around 11.5 gallons for 10 gallon batch...But all this will be different for any brewer you talk to,My advice...Build a system that gives you a chub,then brew the **** out of said system,you will dial it in before you know it.....Then upgrade to a blichmann all stainless Mega dollar sculpture and go pro.....haha J/k have fun with it,dont stress,and remember even if you screw it up it will usually always be drinkable! there are some great calc's out there to calculate water volumes(ex kettle=14" diameter,6" of water(height) equals (x) gallons of water i use these and a yardstick to measure my volumes.

The amount of water you'll need to mash will depend upon the amount of grain you have, since the grain will absorb some of the water. Usually the grain absorbs between 0.1 gallons and 0.2 gallons per pound, but this can vary. Generally speaking, people usually mash with between 1.25 and 1.75 quarts of water per pound of grain, and then sparge the remaining volume, which varies depending upon the recipe.

How much grain you need for a 5 gallon batch of whatever beer will also vary depending upon your efficiency (since this affects how much grain you use), which you don't know if you've never done an AG batch before. So, just pick a number, say 70%, and use an amount of grain appropriate for that efficiency. Assuming you hit your target post-boil volume, if you are more efficient your OG will be higher, and if less efficient it will be lower. You will have to tweak your efficiency number for the first few batches while you dial in your system and get over the initial hurdles.

So let's say you are doing a SMaSH of 2-row and Centennial hops for your first AG batch and want to make a pale ale with an OG of 1.050. 2-row is usually 36 ppg (points per pound per gallon) so to end up with 5 gallons of 1.050 you need 50 * 5 = 250 points.

So you calculate the pounds of grain you need taking your efficiency into account:
250 / (36 * 70%) = 9.92 lbs

We'll just round that up to 10 lbs to make things easy.

Assuming your target boil volume is 6 gallons:

Let's say you mash with 1.5 quarts per pound of grain.

You mash in with 1.5 * 10 = 15 quarts (3.75 gallons) and mash for an hour.
The 10 pounds of grain absorbs 2 gallons, leaving you with 1.75 gallons in the mash tun.
Then you drain the MLT and sparge with the remaining volume, which in this theoretical example is 4.25 gallons. In my system I actually add about half a gallon to account for system losses (e.g. stuff left in tubing) and trub, so on my system it would be more like 4.75 gallons of sparge water and my boil volume would be 6.5 gallons.

ok so that brew pot just went out of stock so who just bought the last one from my link? haha just kidding.

They do have the same one in 15 gallon for $100 more. Would a 15 gallon pot be too big for a 5 gallon batch? I feel like its a little over kill. Also i'm a little concerned as to how the 15 gallon would fit on my propane burner but i cant find dimensions for the pot anywhere. My burner is just a turkey fryer burner so I dont know how well it will fit.

I make 5 gallon batches in my 15 gallon pot all the time. HOWEVER, a 15 gallon pot is a lot more unwieldy than a smaller one, and you will probably have a relatively substantial amount of leftover wort in the bottom of your pot if you don't use a dip tube or tilt your pot when you are draining it.