TCP Window Size

Hi

I would like to share my experience. We have a data base application
with record of 30 million people.

PROBLEM : Slow application access from time to time

Server : data base application

WAN : 12Mbps of clear pipe end to end WAN links

client : A Thin and Terminal Server serving 200 thin/terminal server
clients

Util% : WAN links are max 60% loaded

RTT : 20-120 msec with average RTT of 58msec

Server TCP Window Size : 24kByte

Client TCP Window Size : 65kByte

I have strong understanding that this is due to the SENDER and
RECIEVER capacity mismatch

Kindly advise on this situation

What TCP window size should be used ?

Should it be changed on both ends ?

can FAST TCP be applied in this scenario ?

Waiting for your valuable answer

Thanks

.