RH 7.3 Latest Kernel. RPM Install

RH 7.3 Latest Kernel. RPM Install

I am ready to move the server to another co-lo center; and hope this will
the last time. Two times in the past 6 month.

I need to lower the expiring time, seconds in all domains's DNS. I need a
lower TTL and wanted to know based on others that have done the move.
I know that too low of a TTL the root DNSes might ignore it. I also check
and try to stay as compliant as possible with DNSReport
<http://www.dnsreport.com>

Location:
/var/named/run-root/var

I have very few domains, I can easily backup the entire directory and
one-by-one
I can manually change the expiring time.

Here is a current sample of a domain:

$TTL 86400

@ IN SOA ns1.theserver.com. totalrad.thedomain.com. (
123123123132 ; Serial // changed it to
123123132 from orig.
10800 ; Refresh
3600 ; Retry
604800 ; Expire
86400 ) ; Minimum

thedomain.com. IN NS ns1.theserver.com.
thedomain.com. IN NS ns2.theserver.com.
thedomain.com. IN A xx.xx.xx.8
webmail.thedomain.com. IN A xx.xx.xx.8
mail.thedomain.com. IN CNAME thedomain.com.
ftp.thedomain.com. IN CNAME thedomain.com.
www.thedomain.com. <http://www.thedomain.com.> IN CNAME
thedomain.com.
thedomain.com. IN MX 10 mail.thedomain.com.

I know that I will have to change the DNS settings for the NS1.theserver.com
and NS2.
Basically the "Theserver.com" domain. All domains on the server uses the
'theserver.com'
their 1st and 2nd NS.

Anyone suggest a Refresh, Retry, Expire and Minimum time in order
for the server and the DNS to propagate faster and not have as
much down time.

I know once I change all domains, and DNS I will let it sit for
at least 2-3 days than do the switch.

Thanks for any inputs, if I find anything on search engine, I'll post back
here.