HI! So I'd like to do an extraction, but I have a couple problems. I'd like to reduce the solvent quickly. So my idea is to get a hot plate, put a big pot with hot, or boiling water, and then put a big bowl with the solvent in the water so it evaps faster. Anyone done this? Could there be a loss of product from solvent heated to around 90 C? Thanks.

Sister has done this, basically double boiling. Its safe and efficient as long as your hot plate is sparkless. Some of your product may sublime up the edges of the container, but it isn't lost.

Should be perfectly fine just make sure no one is smoking near it and theres no sparking appliances nearby.(refrigerator air compressors spark and furnaces usually have open flames). Best done outdoors or with good ventilation.

In addition to what has been said I would note that a fan will speed up reduction greatly. But on top of being risky your reduction method is wasteful and harmul for the environment.

I did it may times until I bought a lab distillation setup. Now I can recover ~80% of solvents, some of which are hard to find.

You can buy a suitable setup for 50-90 USD on ebay. It will serve you for many years and will save you a lot of solvents.

Usually I keep reducing combined extractions until the boiling solvent becomes cloudy. It is a sure sign that it is concentrated enough to start cooling it for crystallization.