May be interested but do not know much about this carb or its applications. Please pardon the inquiries - and if this is more than you want to deal with, I understand.
No problem, I will answer any and all questions to the best of my knowledge. Be fore warned though, some people are very opinionated about their carb choices and applications.
s it a dependable type (free from a lot of tinkering and adjustments) and does the 600 CFM rating make it applicable to standard 350 SB and 402 BB applications (compared to Q-jet of same apps)?
It is a Holley mechanical secondary carb, which in my experience is about as dependable as carbs get. In general 600cfm is enough for a warmed over 350 or a mild 402. If you are looking to tow, some like a smaller 2 barrel carb better for more torque. For street driving and strip duty 600 is about right.
Looks like it requires a fuel line setup that will feed two inlets - correct?
Yes, you need something like this to hook it up.
http://www.summitracing.com/parts/SUM-G3110/
May I assume that the mechanical secondaries are activated my an extended position of the same control rod that operates the primaries, and is this an easy bolt-up fit for the fuel feet rods for engine types noted above?
Yes, the mechanical secondarys start opening about 1/2 throttle and all four barrels are fully open at full throttle. You can use your factory fuel line from your fuel pump or make a new one to go to the part i linked to above.
Does any manual control choke fitting/cable come with it?
No, you would need to use your factory one or get another.
Let me know if you have any more questions.