full boil 5 gallon batches are going to start with 6 or more gallons of wort once you account for losses to trub, boiloff, etc. if you have ANY interest at all of going to 10 gallon batches (same amount of work, twice the amount of beer) i would suggest using a half barrel keg. it'll do 5 gal batches just fine but allows expansion. as for how to get holes in it, bargain fittings or brewhardware.com (bobby_m here on the site) are both great places to get gear. weldless kits use gaskets and only require you drill a hole. welded kits require a SKILLED tig welder to do correctly/pretty. there is a halfway option called "SS Soldering" where you use silver solder and a dimple tool to make a mechanical bond that is water tight. i SS Soldered all my fixtures in my latest setup and love it. slightly more work than weldless but a lot more sturdy. there's a link in the DIY section that can give you the info.