Why not use just plain old shoe wax/polish? The old style in the round metal tins? FWIW, I use furniture polish on my leather sofa...works great. Might not want your boots to smell 'lemon fresh' though!
I'm not sure you couldn't use mink oil on the dress boots. Can you test, say inside ankle portion of the boot where it wouldn't be so visible?
I use silcon spray on my work boots to keep them waterproof. Don't think I'd do that on the dress ones though. Hard to say as the outside finish of the work boots is totally different and you can't tell what will happen on a flat/gloss finish shoe. Unless you have an old pair of leather shoes you could test on????