So I accomplished the redistribution task in a slightly different way. My reasoning for this is that increasing the OSPF External AD above 170 when doing mutual redistribution with EIGRP, doesn't really accomplish anything. Sure, EIGRP external routes going into OSPF wont get looped, but now you have the reverse problem of External OSPF routes going into EIGRP!
If the sub-optimal routing of OSPF external routes is acceptable, why not sub-optimal routing of External EIGRP? We might aswell not change the AD in OSPF at all.
R1:
ip prefix-list BB3 seq 5 permit 30.0.0.0/14 le 32
ip prefix-list BB3 seq 10 permit 31.0.0.0/14 le 32
route-map FILTER deny 10
match tag 22
!
route-map FILTER permit 20
!
route-map EIGRP100_TO_OSPF permit 10
match ip address prefix-list BB3
set metric 999
set tag 11
!
route-map EIGRP100_TO_OSPF permit 20
set tag 11
!
router eigrp 100
redistribute ospf 1 metric 1500 100 255 1 1500
router ospf 1
redistribute eigrp 100 subnets route-map EIGRP100_TO_OSPF
distribute-list route-map FILTER in
R2:
ip prefix-list BB1 seq 5 permit 212.18.0.0/22 le 32
route-map FILTER deny 10
match tag 11
!
route-map FILTER permit 20
!
route-map EIGRP100_TO_OSPF permit 10
match ip address prefix-list BB1
set metric 999
set tag 22
!
route-map EIGRP100_TO_OSPF permit 20
set tag 22
router eigrp 100
redistribute ospf 1 metric 1500 100 255 1 1500
router ospf 1
redistribute eigrp 100 subnets route-map EIGRP100_TO_OSPF
distribute-list route-map FILTER in