Question: Is there a software that allows me to customize and fine-tune my drawings with precision control and third-party models?

If you want to be able to fine-tune your results and incorporate third-party models, Invoke is a good option. It's a generative AI platform for professional studios with tools like control layers for fine-tuning, a workflow builder for customizing, and the ability to upload your own models with Hugging Face integration. It also has support for team collaboration and role-based access controls, so it's a good option for serious use.

Another option worth mentioning is DrawingPics, an offline AI art generator. You can generate images directly on your computer with a range of stable diffusion models and LoRAs. DrawingPics has a whiteboard interface for Mac computers, 'Draw to Real' for refinement iteration, and Precision Control mode for more precise line drawing. It supports custom models and LoRAs, and offers a range of pricing options, so it's good for artists and designers.

If you want an AI-assisted drawing tool on your iPad, Muse Pro is a good option. It uses GPT-4 Vision to generate high-quality results and has real-time AI guidance, layers for experimentation and a library of brushes. Muse Pro works with Apple Pencil and lets you fine-tune AI control with intuitive sliders, so it's a good option for artists who want to get more out of their creativity.