Just do it on 30d visa exemptions but really have your 'aways' at least a month, try to organise your 'aways' to exceed your in-country days, have the 3proofs, if it gets tricky thats your cue for the Laos / Cambodia holiday
as i understand it, in the application process, you have to show proof of pension, which is the contradiction to the age req. of course then the OA visa leads to the Med Insurance trap