IDK how you can coat at 70F. This is low enough for the gelatin to begin setting up. Usually, coatings are made at 100F. As for these coatings, the gelatin does indeed swell and shrink while the support does not do that very much. You can use alcohol instead of PF200, but you might try cutting down on the amount of PF. It is bad without but can be as bad with too much.
Why not use the Melinx? Because the mfgr wants a minimum order of 8 master rolls of full width and length. This would impoverish everyone but Bill Gates or someone like him!