I haven't looked up the cams you intend to use. But, anytime you change valve springs. You must know what your installed height is. What the spring pressure is at that height and adjust, if possible, to get the correct specs. This will include. Different retainers (no rotators!) available in many heights. Valve locks, in many groove heights. shims from .005 thru .060" in correct diameters for your particular heads. Pockets can usually be cut for larger springs. Tho yours are thin and not much material to work with.
Then you must provide stem seal to retainer clearance and seal to spring clearance, then provide for over the cam nose pressure and stack height.
Not for the hobbyist with no tools and experience.. Thats why I have over twenty stocked drawers with the afore mentioned parts and a large shop full of tools.
Better to have it done correctly than to loose a flat tappet cam/lifters and bottom end bearings. I see this almost every week lately..