It would be best to replace everything with known items.
Triple springs suggest very high rpm roller lifters. You would only need them for something like an 8,000 rpm engine with solid rollers. Those do not appear to be stainless valves to me.
You need to be concerned with your pushrods with those springs and you could be putting yourself into needing a rebuild every 500 miles or so using that much pressure. If that's the type of engine that you want, then go for it.
7/16", screw in rocker arm studs are what you want and I would say that neither the intakes or exhausts are what the current configuration of high performance stainless valves look like. They look like TRW replacement valves. The entire mix of specs is screwy.
Most now are going to have some form of cutback stems in the valve pocket area and have indication of full machining on the tulip portion of the valve.
Many manufacturers stamp or lazer cut part numbers into the stems near the tips. Look there for numbers.
If it were me, I'd replace the entire valve train and install new guides as well.
It would be advisable to take them to a shop that is familiar with high performance Fords.
Also, using triple springs with bolt down rocker arms seems a conflict of terms. That's only a 5/16" bolt and the rocker arm fulcrums are cast. That combination is just a disaster waiting to happen. Mahem is hiding in the wings.