I am the proud owner of a new-to-me Puhui T-962. This is a reflow oven that can be bought fairly cheaply, but because the manufacturer cuts corners in several places, you have to do several modifications to make it usable. The main thing I did was install the replacement firmware written by Unified Engineering, and replace the masking tape (!) with kapton tape.
Either firmware allows you to configure two custom profiles. You specify a target temperature at 10-second intervals. Unfortunately most solder paste datasheets don’t specify at 10-second intervals; rather, they specify times and target temperatures. Here’s an example from MG Chemical for their 4902P low-temp, lead-free paste:
It’s difficult to “eyeball” the interpolated 10-second intervals here. They only give a bullet every 25 seconds, and you even have to guess those temperatures!
So, I made a spreadsheet—you can download it for yourself. It will do a linear interpolation of the points you give in columns A and B. If you need more interpolated times, be sure to extend columns E thru I, which are hidden for clarity.
The license for the spreadsheet is CC-BY-SA, meaning you can use it commercially as long as you retain the copyright notice. Hope this saves you some time!