Just my opinion, so if your mind is already made up, you can ignore me...
A friend of mine and I were talking about Healeys (he restores them, Morgans & Triumphs for a living) and aluminum sumps; neither of us could ever recall seeing a Healey that did not have a dented oil pan. Collectively, our history of Healeys goes back over seventy-five (>75) years, and both of us worked (or still works) on Healeys on a daily basis. Neither of us would even consider an aluminum sump, unless a thick steel plate was utilized to protect it__negating any weight savings and blocking any cooling air flow.
If a steel oil pan meets with an immoveable object, it will dent, and if severe enough, you can bash it out. The same cannot be said of aluminum, as it will crack/shatter, with an immediate impact on your oil level...