It seems PAL checks my wife every year for her carry on, 15 lb. She is always over.
Me I have my backpack and they never ask me as I make it look as though it is light as a feather, but is probably close to 20lb. I believe you can bring one carry on, plus one laptop, plus one "purse". Of course the size of my wifes "purse" is the size of a shopping cart.
Don't forget that PAL has lowered it's check in luggage to 50 lb for fiesta class, but it is still 70 lb for Mabuhay class. I have purchased the sport equipment option, which you sign up for ahead of time. The limit is 42 lbs. I used it for all my dive gear. It was a bit expensive, can't remember the exact price now, think $150 per/year. Only did that one year as we needed to bring 5 luggages at 70lb each.
PAL has it's own airport so immigration is quick, but luggage is a hassle. Hire a porter if you have a lot as they will pick it up and take it outside for you for a few pesos.
Have fun.