FreeBSD network settings for highly utilized squid proxy server by dial-up users

Port config knobs:
cat /var/db/ports/squid26/options
# This file is auto-generated by 'make config'.
# No user-servicable parts inside!
# Options for squid-2.6.9
_OPTIONS_READ=squid-2.6.9
WITHOUT_SQUID_LDAP_AUTH=true
WITHOUT_SQUID_SASL_AUTH=true
WITHOUT_SQUID_DELAY_POOLS=true
WITH_SQUID_SNMP=true
WITHOUT_SQUID_CARP=true
WITHOUT_SQUID_SSL=true
WITHOUT_SQUID_PINGER=true
WITHOUT_SQUID_DNS_HELPER=true
WITH_SQUID_HTCP=true
WITHOUT_SQUID_VIA_DB=true
WITH_SQUID_CACHE_DIGESTS=true
WITH_SQUID_WCCP=true
WITHOUT_SQUID_WCCPV2=true
WITH_SQUID_STRICT_HTTP=true
WITHOUT_SQUID_IDENT=true
WITHOUT_SQUID_REFERER_LOG=true
WITHOUT_SQUID_USERAGENT_LOG=true
WITHOUT_SQUID_ARP_ACL=true
WITH_SQUID_PF=true
WITHOUT_SQUID_IPFILTER=true
WITH_SQUID_FOLLOW_XFF=true
WITHOUT_SQUID_ICAP=true
WITH_SQUID_AUFS=true
WITH_SQUID_COSS=true
WITH_SQUID_KQUEUE=true
WITH_SQUID_LARGEFILE=true
WITH_SQUID_STACKTRACES=true

Boot network settings:

cat /boot/loader.conf
accf_http_load="YES"
accf_data_load="YES"

#kern.hz=1000
kern.maxproc=6164
kern.maxdsiz="1536M"
kern.dfldsiz="1536M"
kern.maxssiz="512M"

kern.ipc.msgseg=768
kern.ipc.msgssz=128
kern.ipc.msgtql=3072
kern.ipc.msgmnb=12288
kern.ipc.msgmni=60

kern.ipc.shmall=6144
kern.ipc.shmseg=24
kern.ipc.shmmni=48
kern.ipc.shmmax=51457280

kern.ipc.shm_use_phys=1
kern.ipc.nmbclusters=131072
kern.ipc.maxsockbuf=524288

net.inet.tcp.tcbhashsize=16384

Run-time settings:

cat /etc/sysctl.conf
security.bsd.see_other_uids=0

kern.maxfiles=40960
kern.maxfilesperproc=22190
kern.timecounter.hardware=TSC
kern.ipc.somaxconn=4096