Recently with the Mazda3 front pads I followed a YouTube video example and applied the softened (two layers of cardboard box held by masking tape) G-clamp gently to the exposed back of the outside pad and the back of the caliper.
This simply pushed the piston back and being very finger-tip easy proved the sliders were still free.
Undo the bottom bolt holding slider to caliper, swing caliper up clear, lever out the pads and clean everything.
Re-assemble with shims in the correct orientation and just enough grease in all the right places.
A touch of medium thread-seal on the bolt to the slider sleeve and torqued up to spec.
About fifteen-twenty minutes a side with a trolley jack under the sill jacking point, and an axle stand right next to it just in case. Most of the time was in cleaning the caliper and shims etc and checking the tyres and discs.
I would strongly advise some form or additional help when doing the rears as well. The splined adjuster is made of cheese and if you rely only on that it is likely to be an emotional situation when it comes to the rear pads.
The spline adjuster is soft pot metal; perhaps deliberately so (about £5-10 from Mazda). Make sure you have the right allen key fitted. Its too easy, because you are working blind, to pop in the wrong one, and end up rounding it. You can hook out the adjuster, and check. Its also easy to fit an allen key, and half retract the spline while adjusting, damaging it.