Well, pay for the larger SWG or pay to have to run your pump nearly 24/7 to maintain adequate FC. That is the trade-off.
Now given your location, the sun is less intense, so perhaps you could have lower daily FC losses.
Let me wow you with math
The T-15 produces about 1.4 pounds of chlorine gas running at 100% for 24 hours. In a 38k pool, that equates to 4.4ppm of FC.
A typical pool needs 2-4ppm of FC daily.
If you get lucky and are on the low end of that, you would need to have the SWG running at 100% for 11 hours to add 2ppm. So your minimum pump run time will be 11 hours per day.
Usually a pool only needs to run for a few hours a day for mixing and filtration, so 11 hours is going to be a significant amount of extra electricity (depending on your rates).