I would advise you to look at below forum post after you do the WDS setup as per the wiki page. It is really simple and works great.
It seems you have a similar setup as this topic and it may be helpful for you:https://forum.openwrt.org/t/wds-network-setting-stp-right/186173/14
Good luck.
Btw: I am using WDS setup, however only with 2 nodes and it is solid. No probs at all.
Kr
K