Optimising Texture Sheets

I have been following tutorials on ways to combine the different texture sheets I have made in Substance Painter into one material to save memory while rendering the character. The process I have followed was to export the different texture sheets from Substance Painter in PNG format and then import them into Substance Designer. I then dragged these different PNGs from the explorer into the graph and hooked up the different inputs into one base material, after applying a greyscale to certain inputs such as Metallic.

After doing this for all the different textures I used a material blend node, and a 'rgb-a_split' that separates the alpha channel, to combine the different texture sheets into one, with the end blend feeding into the output nodes and allowing me to export it all as one large, combined texture instead of the four original ones.

EDIT: I also tested the exported textures in Unreal 4 to make sure that export would function correctly and everything works perfectly, I will definitely be able to use this method for all of my assets to save memory for my game.