Okay, yesterday I slid under the garage of my Raptor and found that the factory tie downs are welded into the outer main "I" beams and a heavy center stamped channel. I knew they were welded from a factory tour video I watched a few months ago. Those are the only three spots north south that the 1" heavy plywood floor bolts to.
My B&W Biker Bar bolt in retainer plates have an outer east/west bolt pattern of 27.813" with a north/south bolt spacing of 4.5". The plates are 1/4" thick 4" x 6" and have the usual 5/8" biker bar mounting bolts retainer nut welded to the bottom of the under bed mounting plate.
My outside "I" beams have approximately 1/4" top beam flat metal, same as the biker bar's under deck retainer plates. The center stamped channel has around a 2" wide lower channel with two outward top flanges of around 1.25" wide full length. The center channel appears to be around .188" or just a bit less. The inside to inside of what I can bolt to on both the center channel and the outside "I" beam is 35.75".
There are no east/west cross beams that are in contact with the 1" garage floor. So anything I put in will have to be heavy gauge.
Here is a mock up I did yesterday of what I have after taking some measurements and deciding on what or how I want to attach my Biker Bar to the garage floor.
I'll be up front that I may be a bit anal about this and it may end up being overkill when completed.... But I'm thinking it can't be too strong, just not strong enough.
So here is what I have. The center stamped web channel and the outside "I" beam. The floor they tell me is a one piece 1" thick plywood floor. The floor is cut out for the round welded in tie downs and are flush with the top of the garage floor.
I can have a total of 35.75" wide reinforcement bars, which I think I should put in. B&W says that any floor that will support a bike will work to mount the Biker Bar to. Although having a bit of each under bed mounting plate in contact with a cross brace of some sort would be even better.
Because I have just the two outside "I" beams and the one center stamped channel, my under bed mounting plates will not "grab" anything but plywood. But what I plan on doing is using 1.25" x 1.25" x .25" x 35.75" angle iron as my two cross members and as you can see from the individual end screen shots that there's only a couple inches between the under bed plate and the "I" beam or center channel. Since the "I" beam is .25" and the under bed mounting plates are .25" thick, I plan on bolting the under bed plates through the floor and through the angles. I'll use 5/16" carriage bolt to sandwich the plates between the floor and the angles. The end of the angle iron at the center channel will need to have a 1/16" thick spacer between it and the channel to allow for the 1/4" under bed plate.
The "I" beam end will just be a straight forward sandwich without any spacers needed. I'll bolt the angle iron ends to the outside "I" beam and the center channel. Carriage bolts there as well.

Here is the blow up of the inside channel connection.

Here is the blow up of the outside "I" beam connection.

So with all that said, should I look at any other means to attach the Biker Bar to the garage floor? I plan on using some plastic plugs to fill the 5/8" main attachment holes when I'm parked and have the inside Bike Bar removed.
I'll have (

5/16" carriage bolts holding the under bed lower plates in place plus the added strength of the angle iron and the 1" thick plywood floor. I could upgrade the carriage bolts to 3/8", but not really sure with the sandwich effect if the 3/8" would do any more than the 5/16" bolts.
I plan on making up enough to mount two Biker Bars into the floor. That way I can take both Harleys or the '09 CVO and a Honda Helix. Plan ahead I say...

Although I don't think a Honda Helix will have quite the same stress, but being able to take both Harleys to Sturgis could be fun. I've had both bikes at Sturgis, but not the same years. The Shovelhead ran 1500 miles my first year there without any issues, just wash and ride it.
You guys that run with the Biker Bars, do you think that I'm going to be good enough without actually having one or both of the under bed mounting plates directly bolted to a cross member?
Any suggestions or concerns would be greatly appreciated. This is just in the pre-cut stages, so changes can still be made in the plans.
Thanks in advance.