1) garage when it's windy
2) I think so, my mash drains are typically 15 minutes or so unless it is sticking.
3) I don't find husks in my boil, what kind of strainer are you using? false bottom or ss supply line?
4) Yes, depending on how thick or thin you are mashing. At 1.3 qt / lb. I am usually at about 5 gallons for the mash. I've been playing with a thinner mash lately 1.8 qt / lb and am typically over 5 gallons. I use my 5 gallon pot and I have another pot that I use if I need more than 5. I heat mash and sparge water on my kitchen stove, not sure if that's an option for you. I do that as it's cheaper than propane. I boil my wort outside w/ propane.
5) you can if you want, you will thin out your wort and will likely miss your target SG. What you really need to work on is knowing how much your system evaporates over the course of 1 hour. I burn a bit more than 1 gallon in one hour. so I shoot to have about 6.75 gallons pre-boil.
So, if I'm starting w/ 5 gallons mash water, I'll get something like 3 gallons out of the mash. Then I'll do 2 batch sparges of a little less than 2 gallons each, something like that. Then, after an hour boil - I'll know that I'll end up w/ about 5.5 gallons into primary.
Its just a matter of practice and taking good notes, then reviewing those notes prior to your next brew. I created a little spreadsheet that I use on each brew session and I mark down all kinds of things (gravity of mash, gravity of both sparges, preboil gravity, gravity into fermenter, final gravity, abv and any notes - such as, "don't boil outside on a windy day
There are all kinds of people on this site who are really helpful. Check out some of the info from BrewKaiser. Here is a good thread from some experienced AG brewers http://www.homebrewtalk.com/f36/has-...sparge-143646/