PLEASE READ wds hotspot yahoo music wow mtu settings

ok guys i know this topic has been coverd and i have been thru them extensively, and i have a question not covered in those posts.
I have a hotspot network in a small city that consists of all mikrotik gear

1 main ap 1 watt amp 2 cm9s in B only mode running wds no nstream, connected to my dsl modem from ethernet 1 with a mtu mru setting of 1300 as reccomended.

7 remote hot spots running wds bridge using a 14dbi yaggi and sr2 for the input and a sr2 with 12dbi omni for the output to my clients. Each of these also has a ethernet port bridged in to allow internet access for the people that are allowing me to host the hotspots on thier properties

Ok here is the problem , i have great signal of 65 tx and 65 rx on my remote hotspots , but am having trouble with yahoo music and some games from playing. Im getting a very sparatic ping ranging from 20ms to 2000ms from differnet sites, sometimes on dslreports i can pull 4 megs and sometimes its at 300kbps. My signal strength is pretty much within 64-74 on tx and rx, my ccq is around 86/64 overall is around 90.

Questions
1, Do i need to set a lower mtu mru on the hotspot wireless /ethernet interfaces or just at the main ap where the dsl is at?
2. Should arp be enabled or disabled on my remote hotspot bridges?
3. How can i get better ping rates?
4. On the wds page of the remote wireless hostpots , it works weather its enabled or not, but i have it set to static and to bridge 1 with the default setting for the cost and cost range?