Beginner struggling with first time PCB etching - advice
If you insist on the toner method, I suggest getting toner transfer paper.

Get a laminator which will (firmly) accept the thickness of your board + paper, and run it through that. Go as slow as possible, and use a high temperature. Let cool, peel off backer. That will transfer the toner without any of the drawbacks of liquid solvents (running, bridging.)