This helped me a lot with the bed’s seesawing.
Tightened the “bracket” bearings in one of the Y axis linear modules as described in the forum in the below link. Check out the before and after videos at the bottom.
(After taking the bed tray off, the wiggle in the bracket was very hard to detect. I could Barely feel it and didn’t think it would matter as much as it did. I sat there trying to wiggle both the brackets for a while making sure I wasn’t making it up in my head 
)
Wobble Before (Turn down volume!)
After
So far the prints have become acceptable with the stock bed, not sure how long this will last though. I also have the tray without the square border if it matters.