Workflow I have been using to run my fine tune of PixArt Sigma.

I'm still looking for the best settings. More steps usually gives a better image.

You need the extra models node package. https://github.com/city96/ComfyUI_ExtraModels

If you have the vram you can set the T5 loader to use gpu instead of cpu ram.

T5 files go in the models/t5 folder: https://huggingface.co/PixArt-alpha/pixart_sigma_sdxlvae_T5_diffusers/tree/main/text_encoder