Question, Mumble: Have you considered building multiple classes of tiny hull 1/1 ships? For example, 17k fodder-class armed rowboats mark 1, followed by 17k mark 2s? The upgrade cost would be less, possibly allowing a second upgrade cycle. Has this been tried and shot down?
Yes I have, but you have to build all ships first and then do the upgrade. The reason is your economy can *never* recover.
The upgrade costs over a billion bc's (17K upgrades * 60K per upgrade = 1 billion bc) so you start out that much in debt, however once you've done the upgrade of 17K ships your ship maintenance costs exceed 3 million bc's per turn so even though I'm making 1.3 million bc's per turn, each turn I'm adding another 1.7 million bc's to my debt. You can never recover.
The thing about the 25 attack 460 (size 196) defense versus the equivilent 400 attack 10 defense (also size 196) is the cost of defense is far higher than that of offense. Basically the 25/460 ship costs 6K to build and 60K to rush buy whereas the 400/10 ship costs 2K to build and 20K to upgrade (approximately). You could consider trying multiple upgrades by upgrading to the cheaper 400/10 ship for *only* 340 million but still your maintenance costs will far exceed any possible income you could have so you can never do two batches of upgrades.
But you could build 17K of Ship1 and any number of Ship2 and then upgrade all your Ship1's and I have done that and it does perhaps yield a bit more points but the effect is muted by the fact that you've had to delay the huge boost to your military rating provided by the upgrade by the time it takes to build all these extra ships. All in all I believe the most effective strategy is to build all the ships that you can upgrade at one time and do the upgrade as soon as possible. This also limits the tedium of the method which is no small benefit.
One final point about the 17K number. To my knowledge that has only been verified in DL not DA and I discovered it by basically doing a binary search to find the point where my machine crashed. Dependent on your machine and how many services you have active and how much memory they take this number will vary. I have a very low number of active services as well as a very small amount of memory dedicated to them but at least I don't have to kill my anti-virus for example. However your mileage may vary. Also the speed of your machine shouldn't affect this limit but it will affect how long it takes to do the turn.
With my E6600 Intel Core II Duo @2.4GHz it takes me about an hour to do the upgrade. It can take 10-15 minutes just to *schedule* the upgrade of all 17K ships. On my old machine it took an hour to just *schedule* the upgrade and as near as I could tell close to 4 hours to do the upgrade, I just usually went to sleep leaving it running.
No clue as to the TA methodology in fact the DA methodology is really still being worked at this point. I think DethAdder is the closest to being able to tell us how this works out for DA.