With Express sights the aim is usually meant for the bead to be buried in the bottom of the V.
With the 3-4" height, a hold only 1/2 way might be necessary.
BW and Vaseline is a better BP lube than BW and Crisco.
60% BW 40% Vaseline, for me, shot identically with SPG and Lyman's Black Powder Gold in several BP ctg. & muzzleloading rifles using slugs.
Swiss BP is more energetic than GOEX or Old Enysford and Scheutzen as well. Swiss has a higher specific gravity, ie: volume measures must be weighed as, per se' a 130gr. measure for Old Enysford will likely hold 140gr. 1 1/2 F Swiss. You will have to adjust your wad column accordingly.
Most guys recommend Swiss 1 1/2F for ctg. rifles.
Note Vaseline is a synthesized petroleum WAX, thus it mixes perfectly with BP fouling, unlike petroleum oils and greases.