Canadian expat over 65 - CPP and OAS implications

This post is targeted to Canadian expats 65 or older who are living in the Philippines for more than 6 months per year. 

I am now retired, collecting CPP and OAS and I want to spend about 9 months a year in the Philippines, 3 in Canada.  This would qualify me as a non-resident of Canada and the government then withholds 25% of these pensions for tax.  If the tax treaty with the Philippines kicks in the withholding amount is 15% as I understand it.  My current tax liability for these is around 12%.  I am aware of the NR5 form which, as I understand it, might allow me to continue to file a Canadian tax return and pay the same tax, i.e. 12%.  But it's not perfectly clear if that's the case.

I am inquiring what arrangements other Canadian retirees have made regarding the CPP and OAS pensions.  Any information or guidance would be most appreciated.