If you would like advice on migrating from one RP to another, it would help if you could give us a diagram of topology. As EOGRP is onvolved, and you have a mixture of "major" networks, I'll make one suggestion "blind"
Turn off auto summarisation.
EIGRP will summarise at major network boundaries. If all your 10 networks are together, and all 172.16 is together etc, it won't be a problem, but if it has been done using 10 addresses for users, 192.168 for servers and 172.16 for WAN links, while that may look nice and organised, that is probably the worst possible topology for otherwise default EIGRP!
How to migrate - there are a number of approaches.
Big bang - turn one RP off and the other on. Only practical on small networks, but has least chance of conflict.
Parallel running - run both. Can needed. Admin distance for the new protocol should initially be longer than the old one. Confirm by checking topology then shorten the AD to bring it forwards. Can be risky, aprticulalrly is summaries are being done.
Phased - this depends upon a suitable topology, but with a hub/spoke type topology you can enable the new RP on the core and then switch off the old and add the new on each spoke in turn. Similarly if one has a network with obvious regions, this may be appropriate. If the network is to carry user traffic at the same time you will need redistribution between the two routing protocols, but that in itself carries risks.
With larger networks a combination may be needed - phased, and either big bag or dual running within the region.
If I am honest,I would be tempted to readdress and change RP at the same time - enabling the new RP for the new addresses, and having a single redistribution point as I work.
I would also be tempted if doing that to look at OSPF, and its area and summarisation features.
