For an iron sighted rifle with relatively generic hunting bullets, worrying about flat base versus boattails is stepping over dollars to pick up dimes.
I can put together pretty small groups without much practice and without much load development, be lying if I said I was confident that I can shoot the difference between a boattail and a flat base, and I know I’m NOT lying to say if I CAN (surprisingly) shoot a repeatable and measurable difference between the two, then I KNOW it’s not enough difference to matter for anything I do.
In theory - which I do believe is supported in practice - flat base bullets have advantages in their favor, at least for short range shooting. More bearing surface (more grip on the lands), shorter overall length (easier to stabilize), less vulnerability to base disruption in the bore... but these advantages only reveal themselves as tangible improvements for exceptionally skilled shooters and under the right circumstances.