I have to say the new Beta 8 allowance for multiple instances of the Strength upgrade really bugs me. I'd ban it from my home game, but even as part of the general rules I don't think it, nor the Strength upgrades in general, convey the flavour adequately. With the most recent changes, a lucky Force user with only FR2 and all the Strength upgrades could potentially move Star Destroyers or even the Death Star, and this is never seen, at least in canon. Even Yoda is visibly working to pull an X-Wing out of a swamp and move it to dry land. Even Yoda is visibly strained preventing a huge fuel tank from crushing Obiwan. These are at most Silhouette 3 objects, even the tank.
One solution, that would allow it for those who want it in their games, and limit it for those who think it's ridiculous, might be to double the cost in Force pips for each Strength upgrade invoked. This would at least be in keeping with the nature of Silhouette in the game. Silhouette size increases are generally geometric in nature, and it would make sense that the cost of an upgrade invocation would be geometric as well.
In fact, what would make even more sense is to have to spend a Force pip for each Silhouette increase beyond Silhouette 1. That would be considerably more in keeping with canon.