What tips, tricks & techniques for adequate center-support of a foundation?


I’m wondering what methods are acceptable for proper long-term center support under a foundation. I’ve read things ranging from steel cross-braces to car jacks to cement blocks. I was originally going to use 12-guage superstrut beams, but over the long haul I suspect those are going to corrode and probably have a “metal” smell to them as well. So I am contemplating using three 2x4’s to support my queen foundation on a wood rail bed. Would that be rigid enough support?

Interested in hearing what others have used, along with any other ideas, warnings, suggestions, etc.