Sorry I left earlier and didn't get to your questions...
If you're not overseeding you don't really need to water your grass between Oct and April. At all. Then in the spring water 3 times a week for about 12 minutes. In the summer you can water every day. Thats probably why you've got weeds. We use roundup for weeds in the rocks and pull the ones in the grass by hand. You can get good roundup at HomeDepot, etc, but you can buy the commercial strength stuff at commercial landscape distributors. Its just more expensive.
Re: EXL311 - you here?