I have a customer who wants to replace (4) Separate fibers runs
with 50 Micron OM3

(2) of the runs are from building to building with conduit
(1) building has a piece of inner duct inside a 4 inch conduit with a exiting fiber in there already my question is this

should I or can I try to send a snake in the inner duct and pull a piece of new fiber in the inner duct I was thinking indoor/outdoor or should I try to pull a piece of outdoor armored just in the conduit there looks like theres plenty of room The inner duct looks like its a 1.25 wide

I know I could probably use the exiting piece of fiber for a pull but I would prefer to leave that in place to prevent any down time

it is a school and the work will be done in summer

The other run is just a 4 inch conduit which I pulled the exiting cable a while back

so I was just going to use the outside Armored for that

Any Thoughts would be greatly appreciated