I've have concerns that these ships may be a bit too slow. I think the range may need to be extended. Also the jump prep and especially cool down times may need to be halved.
The range isn't the issue. I wouldn't mind some sort of cooldown on jumps. That could be ok. Make a jump, explore the nearby systems, do some mining, do some material gathering, find some interesting stuff, then jump again.
But as it stands, it appears that every jump you're going to have to spend a couple of hours at least mining specifically for fuel.
Assiming Tritium is fairly easy to find in icy rings (i'm waiting to see if this is the case... if its rare, then that won't be funny) then i think 100t would be more than enough.