No. Yes. Maybe.
Normally an engine with A & B transfers would have the A ports crowded forward, closer to the exhaust, which of course would enable more options for sizing and aiming the B ports. As it is you'll have various limitations with added B ports. But I guess what it comes down to is will the additional transfer ports provide enough benefit to warrant the time and effort required to cut them. My gut feeling for what it's worth (ie. nothing) would be to leave it be for now, and just try to get it on the dyno within a reasonable timeframe. Once it's on the brake, broken in and tuned you'll have some good baseline data to guide you on the way to reaching your target. I'd be trying to avoid getting sidetracked til then.
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