So the fact that you have an ozonator and do not plan to use the spa every day or two (just a couple of times a week) would make you a better candidate for using the 2-step bromine system where you use sodium bromide in the water to have the ozonator produce bromine in between soaks and you add additional oxidizer, such as bleach, after your soak to handle your bather load.

On the other hand, if you are willing to maintain the spa every day (missing one day is OK), then you could use the Dichlor-then-bleach method, but you would have to dose every day since ozone reacts with chlorine so your 24-hour chlorine demand may be around 50% or more. Since it's easy to switch from chlorine to bromine without needing a water change, perhaps you could start with this approach and see if it's OK. If the maintenance is too much for you, you can then switch to bromine.

As for the rising pH, with either of the above methods you want your Total Alkalinity (TA) to be lower as this will lessen the rate of pH rise. You can lower your TA to around 50 ppm and then add 50 ppm Borates (usually using boric acid, though you could add 20 Mule Team Borax and acid separately) for additional pH buffering. To lower TA, you can look at the Lowering Swimming Pool Alkalinity thread and can use aeration from your spa jets to speed up the process.

The Dichlor-then-bleach method works by you initially using Dichlor as your source of chlorine until you build up around 30-40 ppm CYA. At that point, you then switch to using bleach as your source of chlorine. Two people for 15 minutes in a hot (104ºF) spa would normally require around 2.5 teaspoons of Dichlor or 1.8 fluid ounces of 8.25% bleach to oxidize bather waste, but with an ozonator the needed amount may be half these amounts. The real rule is to add whatever amount is needed after you get out of the spa so that you measure a residual FC 24 hours later. After that, you add whatever is needed to maintain that residual. The residual should be at least 2 ppm FC though just before your next soak you can have it drop to 1-2 ppm FC since people tend to not want to notice the chlorine or chloramines during their soak.

If you decide to go with the bromine system, then you would add sodium bromide to create an initial bromide bank and add chlorine bleach after your soak to handle your bather load but have the ozonator maintain the bromine level in between soaks. You may need to adjust the size of your bromide bank or the on-time of your ozonator (or circulation pump if your ozonator time is tied to that). 4 ppm is the minimum bromine level. Some people do not like the smell of bromine and you might on occasion need to shock the spa with chlorine to keep it clear, though that is less likely to be needed with an ozonator.