When I first built my streamliner, having no idea really what I was doing nor how fast it might go out of the box I pulled two pistons from my 4 cyl to run as a 1 liter. I probably should have pulled the 2 and 3 as you did but regardless it worked. I made up bob weights with bearings for proper clearance and oil control. I think you need to do this though I have seen people talk about just using two rod caps bolted together but I think for proper balance and protection of the crank you should have proper bob weights. Someone with real machining/engine balancing expertise may opine about this. Anyway it worked for me. However you do it you must control the oil flow.
First year out with my car it was wet, short course only, geared for well over 200 so my runs got me to second gear (of 4) only. Record. Tore engine apart, put the other two pistons in, replaced the valves in the head (DOHC), went 50 mph faster, and got to 3rd gear. Record. Just short of 200 club speed so we went to junk yard back when Wendover had one, found a gear set and were in the process of changing the R&P hoping to accelerate better off the line when it rained again. Embarrassingly slow by todays standards but that was 1984 (after '82 and 83 rained out. El NIno) Turbo after that bumped things up but that's another story.