N.B.: The set bonus of [Sacrificial Steel] + [Sacrificial Pressure] put the actual crit chance at 110%, which means a guaranteed yellow, and chance of some orange crits without any benefit from the Gladiator set bonus on the combo counter.

By putting Drifting Contact, Shattering Impact, and Gladiator Might at (max rank -1), and [Primed Reach] at Rank 6, it removes the need for Umbral Forma.

Your melee weapon should ideally have as many of the Gladiator mods as possible (I use all three), and perhaps some Gladiator mods on Valkyr as well - I use Gladiator Finesse. Whilst Blood Rush and the Gladiator mod set bonus when equipped on her Talons does nothing, the Gladiator mods on your frame and/or equipped melee weapon will apply to your [Talons].

If you are running with Gladiator Rush on your equipped Melee weapon, you should be used to a combo duration of around 7s anyway, so more is not necessary; besides, if you're not hitting anything with your [Talons] for 7.5s you're just wasting energy or you don't care about building up a higher crit chance and are just using it to avoid damage anyway.

I removed the top rank from Shattering Impact and Gladiator Might as I felt these (armor reduction of 1, critical damage of 10%) had less of an effect on the usage of her [Talons] than if I was to reduce the rank of Primed Reach, but then I use a polearm melee weapon and I don't like the short range of claws. With the extra range you can relatively easily [Swipe] at the edge of Nullifier bubbles and not get taken out of Hysteria, for example.