Lethality Varus with LDR as %pen item?

Hubris -> Ghostblade -> upgrade Tear to Muramana -> Serpants fang -> LDR -> IE

Before I start: **The picture is from a recent ARAM Mayham game**, for those interested I will explain at the end of the post.

**But first to the question of the post:** LDR got the Giant Slayer passive back, which is saying: "Deal up to 15 % (based on target's bonus health) increased damage against enemy champions".
**Would it make sense in SR when playing ranked, to go LDR instead of SG** when facing bruisers or the enemy team having "beefy" mages like Brand, Lillia, Zyra etc that mostl build AP items that also give HP like Rylais, Liandry, Bloodleter etc? If enemy team has multiple tanks and bruises then obviously Lethality is the wrong play and one should build On-Hit or AP, but assuming enemy team has Darius Top, Wukong Jungle, squishy ADC but 2 of these "beefier" mages like Brand mid and Swain support.

Both LDR and SG give 35% armor penetration but SG additionally has slightly bigger AD and haste: +10AD, +15AH and a slow on ability hits if enemy is below 50% HP.
LDR only gives +25% crit chance which is useless in non-Crit builds so would you say the% damage amp scaling with bonus HP is worth it or stricktly ALWAYS go SG?

You can skip this part if not interested in Mayham:
Now I obviously wouldn't build this in ranked to be clear.
I was having a great time this match one-shotting Yone, Ashe, and at first Brand as well before he had 3 HP items + Zhonya, but the Darius was receiving no significant damage from me, so I was struggling with what to pick - Seryldas Grudge or LDR?
But then I hit level 15 and rolled one of these augments giving 25% crit chance + some ability, which is why I decided to go LDR into IE with 75% crit chance, which later after getting 2 anvils with +8% crit chance became 91%, so I transitioned into Crit in the endgame thanks to augments and anvils. Hubris had a gazillion stacks, Muramana great as always, Ghostblade was practical because I don't buy boots in ARAM or sell them for an item late game, Serpants Fangs because the enemy Milio kept saving my targets and noone else was going to build it.
I also got EXTREMLY lucky with my Augments

Rolled Augments:
- Blunt Force (increases attack damage by 20%"
- From Beginning to End ( Dark Harvest + First Strike)
- Upgrade Hubris (upgrades Hubris, now it heals you for 2.5% (+ 0.5% per stack) + gain 10 (+ 5 per stack) move speed for its duration, additionally gain 250 gold)
- Soul Siphon (basic attacks that crit will heal for 12% of damage dealt, gain 25% crit chance)