One thing I noticed while attacking oponent spaceport (or any other ship/station for that matter, but is most obvious on spaceports) is that spaceports recharge their shields during combat thus prologing the time it takes to knock shields completely down, resulting in more overral shields strength the opponent needs to damage (initial shield strength + recharge amount gained during combat). I didn't calculate but for spaceports it worth noting down what result in more overal shield strength, talasos or deucalios.
The more shield generators something has, the more likely a shield generator with a high recharge rate and low maximum strength is to be better than a shield generator with a high maximum strength and a low recharge rate, because the more shield generators it has, the less likely it is that the shields can be penetrated before shield regeneration becomes the more significant factor in effective shield strength. It's actually the smaller ships and stations which are more likely to benefit from Deucalios Shields, assuming that enough time passes between engagements for the shield to reach full strength, because they're the ships which won't have enough resilience to last long enough for shield regeneration to matter in big engagements ... but the Deucalios Shield takes a lot of time to reach full strength, and if you cannot ensure that enough time will pass between engagements for your ships to more or less fully regenerate their shields, then it is entirely plausible for ships equipped with Talassos Shields to go into engagements with stronger shields than ships with Deucalios Shields even before taking mid-battle shield regeneration into account.
Also, for most designs, you're going to be able to mount more or less exactly as many Talassos Shields as Deucalios Shields. The difference in maximum power consumption between even 100 Deucalios Shields and 100 Talassos Shields is only 60 energy/s while the shields are regenerating at full rate, and an unupgraded Fission Reactor would cover that. Even if you have to give up three shield generators to fit the Fission Reactor, you're looking at trading 1 Deucalios Shield for 0.97 Talassos Shields - and I'd be more than a little surprised if you could not find space on something that's investing 1000 size into shield generators for a size 22 reactor without giving up shield generators, because a thousand size invested in shield generators is the kind of thing you don't see outside of enormous space stations.
I'm not saying that it's wrong to use Deucalios Shields on big things, mind you - you can do it, and it'll work well enough. It also wouldn't be wrong to mix Deucalios and Talassos Shields on the same design - you'd get a bit more maximum shield strength at the cost of a bit of regeneration rate or a bit more regeneration rate at some cost to maximum shield strength, depending on how you want to look at it. It's just that the more shield generators you have on a design, the more right using the shield with the highest regeneration rate becomes, because, well, even if it's "only" 130 shields per generator instead of 180, if you've got ten or twenty shield generators that's still 1300 or 2600 maximum shield strength that the enemy may have to beat through before they start hitting hull and armor, even before accounting for in-combat shield regeneration.