Diana Saur
Even in Dooley, the Diana-Saur is a pretty niche choice! So props to Rarran for building around it with some pretty solid success.
As a Weapon that scales throughout your run, you can treat it like a Beast of Burden or Dog and put a similar engine around it.
Essentially, you'll want to become tanky so the Diana-Saur can eat as many Small items as possible and scale after each fight.
Landscraper + Subscraper (Property Survivability)
Landscraper, which Shields, and Subscraper, which Heals, are your main defensive engine. They synergize with each other since they both scale with value and the combination of Shield + Heal gives you coverage against both Burn and Poison builds.
Landscraper
Subscraper
Uwashiwali Bird + Yo Yo (Landscraper Activator)
Since your Diana-Saur casts very slowly, you'll need items that cast quickly and often to activate your Landscraper.
When you have Properties, Uwashiwali Bird is always a good choice in this regard since it gains Multicast based on your Property number.
Yo-Yo triggers for every adjacent item use, making it an ideal item since it allows your Uwashiwali Bird to double dip its Multicast activations.
Note that Rarran found a Heavy Yo-Yo, which helped contribute with a boost of crowd control.
Uwashiwali Bird
Yo-Yo