Meri, thanks for your your encouragement and for sharing your experience! Your place sounds great. I just talked to the agent to see the place again tomorrow with a friend to take a second look. You are right about the badly furnished no-charm places... I will have to see if I can deal with the amount of light it has. I work from home a lot so I need to feel comfortable at home during the day.
They want two months' deposit + one month advance (normal) + commission of 20% which I believe is paid every month. Maybe I can ask if they would consider one month's deposit. Edited to add: Giving them 15,000 pesos in security deposit which will lose its value a lot over the next six months seems like a lot!
My PH is at the end of the hall/i.e. in the middle of the block and although there is enough sunlight, it's not streaming in at all hours of the day. I'm fine with it though and love the quiet. You can always buy some mirrors as well to reflect the light that you are getting and brighten it. And remember you're in a good bargaining position in the sense that you're a desirable renter - long term, foreign, female. Good luck!