I would think that 2 minutes is a very long exposure time, at least for Fomatone. My normal time was around 40s-1m at f/8 for a normal 120 neg that would print well on grade 2 filtration. Yep, increase temp and dilute the developer less. You'll get better prints.
Also, you absolutely have to clean your developer tray spotless before you use it for lith. It's an often overlooked step that is critical. Preferably use a separate tray for lith. And skip the filter. Exposure time determines the contrast. The longer the exposure the shorter the development time and the less contrast you'll see in the final print. Long exposure also increases color intensity in the final print.
- Thomas