Hey,
To, configurable multiple bucket sizes, configure the new property 
 hbase.bucketcache.bucket.sizes
To a comma-separated list of block sizes ordered from smallest to largest, with no spaces. The following example configures buckets of size 4096 and 8192.
<property>
  <name>hbase.bucketcache.bucket.sizes</name>
  <value>4096,8192</value>
</property>