Q1. Just to recap, I see some using target scope of 11, some 12 some 15, as long as ALL target scopes are scope+1, on the lines where the gw is the ISPs, that is the key??
Q2. In this post there is an insinuation of an additive component to adding values to target scope, but not verified. Ignore??
http://forum.mikrotik.com/t/recursive-routes-in-ros-7-x/154802/1
Q3. I never use mangling, its like garlic/cross to a vampire. 
The unrelated question in this series of questions… I see black hole entries at the end of some peoples IP routes and assuming it has a purpose??
(I have seen similar routes for bogons for example, is their a linkage in intent?)
Caveat still using Ver6 (waiting for 7.1.2 stable)
/ip route
add check-gateway=ping distance=3 dst-address=0.0.0.0/0 gateway=1.0.0.1 scope=30 target-scope=10
add check-gateway=ping distance=4 dst-address=0.0.0.0/0 gateway=9.9.9.9 scope=30 target-scope=10
add check-gateway comment=PrimaryRecursive distance=3 dst-address=1.0.0.1/32 gateway=034.xxx.yy.bb scope=10 target-scope=10
add check-gateway comment=SecondaryRecursive distance=4 dst-address=9.9.9.9/32 gateway=034.xxx.yy.bb scope=10 target-scope=10
add check-gateway comment=SecondaryWAN distance=10 dst-address=0.0.0.0/0 gateway=04.yyy.xx.aa scope=30 target-scope=10
Q4. Assuming the default values and relationship between Purple and Light Blue, and Green and Orange (instances of scope 30 and target scope 10) are okay??
Q5. Assuming its the values in RED, that need to be greater by at least one than the scope?? ( if paying attention this confirms Q1)
Q6. Can I make the changes now in Vers6, so that when I switch its seamless?
Just in case one wanted to know how I deal with a VLAN fiber connection that unlike cable, does not switch to the new IP automagically and thus needed a script to take the new values (ISP gateway) found in status to apply to the IP routes. (Associated Script in IP DHCP for Primary WAN.)
:if ($bound=1) do={
:local iface $interface
:local gw [ /ip dhcp-client get [ find interface=$“iface” ] gateway ]
/ip route set [ find comment=“PrimaryRecursive” gateway!=$gw ] gateway=$gw
/ip route set [ find comment=“SecondaryRecursive” gateway!=$gw ] gateway=$gw
/tool e-mail send to=“my@email.ca” subject=([/system identity
get name]) body=" This is your new gateway IP: $gw";
:local sub3 ([/system clock get time])
/tool fetch “https://api.telegram.org/bot-:--?chat_id=--text=At+$sub3+BellFibre+Changed+WANIP”
:log info “Telegram notification sent VlanBell IP Changed”
}