SA round-robin in exim ~ BAYES

[Ronan]

Further to my last post regarding the Mysql Backend to multiple Spamd 
servers. How much difference would there be if I ran the (in this case ) 
2 servers on a round robin basis from exim. So over time they would both 
recieve a fair enough diverse amount of mail to make them practically 
identical in terms of accuracy for our domain... I dont really need both 
of them atm as one machine only ever hits .75~.8 load constanly at full 
throughput.
Would the MySql option be a better future proof method as i coud just 
tag servers onto the 'cluster'.

ronan