Call a dealer and tell them what you told us. You're new to town, looking to establish a relationship, only need 75 gallons, could they maybe top you off when they're in the neighborhood anyway without incurring the <100 gallon fee? You're flexible on timing, yadda yadda.
Get a heat pump and wood stove. Between the three you'll be able to handle energy crises and power outages.
#2 oil delivered is $5.09 here. Price just dropped 20 cents. Is your tank inside? Should be able to run straight #2.
I have run oil to my furnace under specific circumstances. One January a few years back they sold my oil dealer and most of the drivers quit in protest. The dealer was futzing around and not admitting they had massive internal problems, "but if you have automatic delivery you'll be fine." Oh, and it was 10 to 15 below all week.
Did some more this spring when there was arbitrage between skyrocketing delivered prices and a few forgotten pumps. Had most of a tank full but wanted to top off. Even paid some road tax I didn't need to! I find it's best to not use any spout on my jerry can but to just pour smooth and slow and let the flow get going down the pipe so it almost "siphons" more of it along. I have a ratty piece of plywood catch any dribbles.
If you buy Off-road diesel during winter you might get a diesel-kero blend anyway. This matters for your proportions but it has slightly fewer BTUs, which will mess up your value math.