Hello ,
i am not very good in english ,but i think i can help answer in question about real work of N standart.
In my city 5gh band is used allmost all posible chanels ,one radios use 5gh others 5gh-turbo and other then scaning i find about 5-8 N standart radios ,is not good for my network but all working fine 
in both ends i have rb600 with full 8 slots used, 3 cards in one end use 5gh-turbo and one r52n ,in other rb600 2 cards use 5gh-tubo and one r52n.
before i use Nstrem2 to conect these 2 rb600
distance betwen them is 2.4km ,used 4 panel 23db antenas, 4x 5gh 16db wireless cards ,5gh-turbo mode ,bandwidth is about 30mbps in+out.
Now (about 1 weak) this bridge is working on N standart.
used 2 dishes 26db ,i rebuild from one polarization to V+H polarization ,2 r52n wireless cards in rb600.
optimal seetings i tested and used i find then all instaled on tower,optimal frequency is hard to find but 5210mhz is work best there.
other seetings :
AP: ap-bridge mode
set 6 ack-timeout=dynamic adaptive-noise-immunity=none allow-sharedkey=no
antenna-gain=0 antenna-mode=ant-a area=“” arp=enabled band=5ghz-onlyn
basic-rates-a/g=6Mbps basic-rates-b=1Mbps comment=“” compression=no
country=no_country_set default-ap-tx-limit=0 default-authentication=yes
default-client-tx-limit=0 default-forwarding=yes dfs-mode=none
disable-running-check=no disabled=no disconnect-timeout=10s
frame-lifetime=0 frequency=5210 frequency-mode=manual-txpower hide-ssid=
no ht-ampdu-priorities=4,5,6,7 ht-amsdu-limit=8192 ht-amsdu-threshold=
8192 ht-basic-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7
ht-extension-channel=above-control ht-guard-interval=any ht-rxchains=0,1
ht-supported-mcs=“mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7,mcs-8,mc
s-9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15” ht-txchains=0,1
hw-fragmentation-threshold=disabled hw-protection-mode=none
hw-protection-threshold=0 hw-retries=15 mac-address=00:0C:42:3A:C7:CA
max-station-count=2 mode=ap-bridge mtu=1500 name=myssid
on-fail-retry-time=100ms periodic-calibration=disabled
periodic-calibration-interval=600 preamble-mode=short
proprietary-extensions=post-2.9.25 radio-name=000C423AC7CA rate-set=
default scan-list=5200,5210,5220,5260,5310,5750 security-profile=default
ssid=k.n.belaidis.net station-bridge-clone-mac=00:00:00:00:00:00
supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps
supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps tx-power-mode=default
update-stats-interval=disabled wds-cost-range=50-150 wds-default-bridge=
bridge1 wds-default-cost=100 wds-ignore-ssid=no wds-mode=dynamic
wmm-support=disabled
/interface wireless manual-tx-power-table
default seetings
/interface wireless nstreme
set myssid comment=“” disable-csma=no enable-nstreme=yes
enable-polling=yes framer-limit=3999 framer-policy=exact-size
client: station WDS
/interface wireless
set 7 ack-timeout=dynamic adaptive-noise-immunity=none allow-sharedkey=no
antenna-gain=0 antenna-mode=ant-a area=“” arp=enabled band=5ghz-onlyn
basic-rates-a/g=6Mbps basic-rates-b=1Mbps comment=“” compression=no
country=no_country_set default-ap-tx-limit=0 default-authentication=yes
default-client-tx-limit=0 default-forwarding=yes dfs-mode=none
disable-running-check=no disabled=no disconnect-timeout=10s
frame-lifetime=0 frequency=5210 frequency-mode=manual-txpower hide-ssid=
no ht-ampdu-priorities=4,5,6,7 ht-amsdu-limit=8192 ht-amsdu-threshold=
8192 ht-basic-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7
ht-extension-channel=above-control ht-guard-interval=any ht-rxchains=0,1
ht-supported-mcs=“mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7,mcs-8,mc
s-9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15” ht-txchains=0,1
hw-fragmentation-threshold=disabled hw-protection-mode=none
hw-protection-threshold=0 hw-retries=15 mac-address=00:0C:42:3A:D3:C2
max-station-count=2007 mode=station-wds mtu=1500 name=myssid
on-fail-retry-time=100ms periodic-calibration=disabled
periodic-calibration-interval=600 preamble-mode=short
proprietary-extensions=post-2.9.25 radio-name=000C423AD3C2 rate-set=
default scan-list=5200,5210,5220,5260,5310,5750 security-profile=default
ssid=k.n.belaidis.net station-bridge-clone-mac=00:00:00:00:00:00
supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps
supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps tx-power-mode=default
update-stats-interval=disabled wds-cost-range=50-150 wds-default-bridge=
bridge1 wds-default-cost=100 wds-ignore-ssid=no wds-mode=dynamic
wmm-support=disabled
/interface wireless manual-tx-power-table
default seetings
/interface wireless nstreme
set myssid comment=“” disable-csma=no enable-nstreme=yes
enable-polling=yes framer-limit=3200 framer-policy=exact-size
first test before instalation
test made from PC to RB600 ,2.4km distance, RB show procesor 100% busy, one weak after instalation :
