Maris,
That's a lot of stepping on the footswitch if you turn the enlarger lamp on and off for each two-second strip. That and the ramp-up/down problem you describe are easily avoided if you simply leave the enlarger lamp on for the whole test-strip exposure time and simply move the card every two seconds (or whatever interval you desire). Use the metronome function on your timer to time your movements. If you start with the card completely covering the lens, you'll even get rid of the initial ramp-up.
What I do is hold the card over the lens, step on the footswitch and get the rhythm of the metronome. Then quickly remove the card and make the first overall exposure (I start with 7 or 10 seconds). Then cover consecutive stripes of the test strip every interval.
FWIW, you'll get more even exposure differences between test strips if you don't use a set interval, but vary the interval between stripes. I like 30% differences (approximately) for a rough test strip. So, my test strip looks like:
10 seconds initial exposure (10 seconds for stripe #1)
3 seconds on the first stripe (30% of 10 = 13 seconds total for stripe #2)
4 seconds on the next stripe (~30% of 13 = 17 seconds total for stripe #3)
5 seconds on the next stripe (~30% of 17 = 22 seconds total for stripe #4)
7 seconds for the next stripe (rounded from 6.6 seconds; roughly 30% of 22 = 29 seconds)
9 seconds for the next stripe (~30% of 29 = 38)
I usually don't have to refine by making another test strip, since I can extrapolate intermediate times for the first test print. I usually make small adjustments in contrast and exposure time by simply making another print and refine my dodging and burning scheme at the same time.
And, I expose the print with the metronome too, uncovering and covering the lens with the card; no ramp-up/down to worry about
Best,
Doremus