nah man. not too long. interesting. I think its important for foreigners to know about this. If I could do it all over again i would use rock for most of the fill and then i would add a layer of the two kind of dirt i used. i used a sandy dirt initially and a very fine dirt (like what they use to make the grey bricks here). one guy close to my house did that and i thought he was loonie at first only to realise he had done the right thing.
your crack that you can see through... i would also be stressed. there is a kind of cement here... i will try to send a picture here... that is very strong. it has fiber mixed in and i used it on a crack on my retaining wall. at first, on the retaining wall, the crack would come back if i just used wall cement. now, it hasn't shown up yet... cross my fingers. I opened up the crack and filled it in. maybe that could be a solution. i will try to upload the photo later today.
cheers