I put half inch stack of washers and slightly longer bolts replacing the front two bolts in each seat-to-base mount,
It is truly hard to imagine the monumental difference this made.
We are perfectly happy now that they have a bit of back-slant.
The person who suggested/first executed this did a really nice tutorial.
It's unneeded.
Pull a front bolt, get one half an inch (or whatever you like,) longer, stack washers to add the back slant.
It was 15 minutes for the first seat, maybe 6 for the second.
One of the best things we've done to the RV.
And we bought these.
I don't use them, spousal unit does.
https://www.amazon.com/Rhino-Strong-...%2C825&sr=8-16
Butt/back/thigh bolsters. Fully adjustable.