The early F18 used the beams from the 20 foot 10 foot wide Tornado because it was easy to source and that became the standard. Some of the builders are using this same oversized beam now on their F16. Both are overkill and it would be a simple calculation to see if they would be structurally capable of handling the loads without a striker.

If they could it would likely be a bit more flexy. I heard a rumor where Ashby installed a striker on his A class “stikerless beam” anyway because he thought the increased stiffness outweighed the added windage and weight.

The C class have a square truss system built into their designs. This requires the stiker post and its runners to each corner of the platform. They then can have a very light beam set as the truss system, which works off the striker and the standing rigg working together, provides all the structural stiffness at a significantly lower weight penalty than having big overbuilt beams. Looking at the AC45 and 72 they are doing the same thing it appears to me.