Need Loadmaster Help

[adis]

Wasn't sure where to put this question, so I just submitted it to general. I'll put out up front that I am a layman, and know nothing about loading trucks. With that in mind, I am slowly getting my 76 K20 into shape. It's going to be a work truck for projects in and around the house. I am using the standard of being able to haul a pallet of quickcrete or stone (3200 lbs) as my goal. What I'm doing now is, while I have the bed apart, I'd like to throw together some DIY tie-down anchors. The anchors should be easily installed on the fly, be able to safely secure my baseline load of 3200 lbs going up/down my driveway (maybe 8* incline,) be removable, and when removed not leave anything mounted on the bed that will ding up stuff that I slide into the bed (like drywall.) I've attached a sketch and pics of a mock-up I did. The idea is to use a 3/8" grade 8 bolt to tie a yoke made of 1/4" steel and a 3/8" clevis into the frame. Along each frame rail there will be two anchor points, one located inbetween the front two bed bolts and one inbetween the two rear bed bolts. I'd finish off the tie-down system with two anchor points left and right, over the rear axle for a cross-bed tie-down (although these won't be bolted to the frame.) I plan to cut the yoke out of 1/4" rectangle tube, and the clevis out of a gr.8 bolt, and use 2" ratcheted straps. So, I guess my questions are:

- what should the WLL of my system be - 6400, 3200, or 1600 lbs?
- if the straps anchor in front and behind of the load, is the WLL the sum of the individual straps - or the average of them?
- how can I calculate a WLL of each assembled anchor (best guess)
- is bolting the anchors to the frame a good idea or bad?
- do you think this system will do the job based on my requirements?
- is there a better product out there that will satisfy my requirements and be in the same price range (i figure my anchors will cost <$7 each, so $42 + labor)

thanks for any insight/help. - mark