Hard to diagnose from a distance but it sounds like an odd set up. My guess is that the wood boiler and storage is just piped in a big loop to keep the oil boiler warm and then the oil boiler controls take care of the heat.
It does sound like there could be an issue with the type and amount of radiators in the living room. Glass windows really suck a lot of heat out of the room and a cathedral ceiling also introduces issues as the heat ends up near the ceiling and not the floor. Ceiling fans can help a bit bit they also can be regarded as drafty. I have seen more than a few heating applications where the heating contractor skimped on the length and type of radiators in a room, frequently its a layout issue where there just is not enough room for enough radiators. The short term fix is to set the oil boiler to run very hot water temperatures out to the radiators as the amount of heat produced increases the hotter the water supplied. Ideally standard fin tube radiators that most houses have start to really lose capacity around 140 F. With an oil boiler there also is a potential issue with corrosion if it is operated below 140 F so most radiators are sized to put out enough heat with 140 degree water. There are also some "boneheaded" installation where the heating contractor puts in too much radiator for the amount of heat available, this means by the time the water has run through all the baseboards it is too cold to heat. Depending on the number of heating zones in the house this can be issue especially if they send the hottest water to the area that doesnt need it. For an example my parents had similar older home with similar living room. It had one zone for the first floor. The heating contractor routed the hottest water to the living room and then went through the bedrooms and utility room before it went back to the boiler. Had they reversed the flow we would have had to crank up the water temperature so that there was enough heat by the time it got to the living room.
The condition where the boiler is running hotter water than typical is sometimes referred to as short cycling. It means the oil boiler is running frequently to maintain the abnormally high heating water circulation. In this case the wood boiler and its storage slows down this cycling when its loaded with wood but once the storage temp drops below 170 it now becomes a liability as the oil boiler is going to have to heat the house along with the wood boiler and the storage to maintain 170 degrees. Not a great idea.
There is definitely is some speculation in my guess but ideally the oil boiler aquastat should be checked to see that the low setpoint is set at 140 F. In this situation you now have 690 gallons of water that is heated up by the wood boiler to 170 degrees, the oil boiler will not kick on until it drops down to 140. If your living room is too cold at 140 degrees I would suggest chasing the root cause which is not enough heat for the heating demand in the room, you choice is putting in more radiation that is capable of putting out heat at lower temperatures or ideally reducing the heat load in the room by adding insulation to the windows. Unfortunately the old heating approach of putting baseboards on the outside walls just below windows makes it tough as the heat runs right up the cold windows. My parents put in a deflector on the top of the baseboard to push the heat out away from the wall and then put in floor length drapes that sat tight up against the window frames. The bottom of the drapes were tucked in behind the top edge of the deflector so the heat ran up the drapes instead of the windows. The really slick way to do this is buy cellular blinds with side tracks and mount them inside the window frames. I have bought mine from this company in VT
https://cellularwindowshades.com/contact-us. One caveat is the side tracks add some resistance to opening and closing so get the continuous loop type cords. These effectively doubles the R value of the windows but hey are not cheap.
I skipped putting in lower temperature radiators, the folks in many European countries have far stricter energy codes that require heating with far lower temperature water. Therefore they have designed and sell "radiators" called radiant emiiters that can run at far lower supply temperatures in some cases 90 F. The alternative is embedded radiant heating but it can be real difficult to retrofit in an existing house. Radiant emitters will take up more wall space and they tend to be designed for contemporary homes so may not look great in a victorian. The neat trick is if you can run the storage down to 90 degrees using radiant emitters and put in some extra controls on the boiler your 690 gallons of storage acts like its 2 1/2 times bigger so it can store a lot more heat due to the temperature difference. The trade off is that it will take a longer time to heat back up to 170 degrees with the wood boiler. If someone was designing from scratch the sweet spot is probably design for enough storage that wood boiler only needs to run every 24 hours in the coldest weather and that it would take 4 hours to do it which lines up with the evening hours.
