I used two of those throttle plates, ca125 mixers, twin SU manifold on a L series.
It was very difficult to get mixtures lean enough, had to run extra idle mixture shims(fitted in the air valve).
This set up even when properly dyno tuned was not as responsive, not as economical and only marginly more top end over a single CA 125 mixer...I also tested a CA 200 mixer but the 125 was better..

But gas injection made another 20KW over a CA 125 mixer on my A series..