I have an old 4-element toaster oven I've been using, with a thermocouple to an Exar (?) brand multimeter. Just controlling the temp by hand using the temp knob - full on to get close to preheat temp, back down to turn off to let it soak and slowly ramp up a little more, then full on up to reflow phase, back down again (some, to like 425)while it ramps to ~230 & hold for a minute, then full off to start cool down, open door at 200 to complete cooling.
Have done 3 runs like that with 1, 2 and 4 small cards with 6 chips and some Rs/Cs and crystal. Only issue has been uneven application of solder paste, needed some touchup, and 1 twisted uC that had to be hot-air removed & reinstalled, and then some pin touchup by hand for not quite connected pins.
I have parts to make a reflow control card. Just need more hours in a day!