That 'tribute' rule means things just got a lot harder.
It's rather doable... provided you actually get immigrents. For whatever reason I never got a single immigrant wave; it might have had something to do with starting in Summer, I'm not sure, didn't even get any messages saying that there were no migrants that season. Checked my d_init, and it's fine, so it was just weird. Made things prohibitively hard with just seven dwarves and only 1 1/2 seasons to put together the tribute. Had I either gotten immigrants or started in Spring, it wouldn't have been a problem. C'est la vie.
I had plenty of wealth to get the first tribute actually paid with enough left over to actually do some trading, just didn't have enough hauling labor to get it all to the depot in a timely manner.
It didn't help that the only dwarf with appraisal skill decided to take a nap right as my haulers finally started getting enough goods to the depot.
It might be worthwhile to pro-rate the first year's tribute based on when the player starts. Start in limestone and add 1k to the tribute value for every month before limestone that a player starts, maxing out at 10k if they start in the beginning of winter or before. That should account for the different starting times. From there, 10k is added to that value each year. That would make the first year less punishing for those who don't get a full year to make tribute.
The other thing I didn't do was build trap weapons. If I'd done that, getting the tribute together would have been a cake-walk. A handful of silver spiked balls would have paid the whole thing off without a sweat. Since I don't normally use trap weapons as a trade good, I didn't even think of using them until after my turn was already over. Woops.