I agree defenantly your idles are way too small, and so are your main jets. Your engine is starving for fuel.
The reason the engine works well when you floor it is because it is getting extra fuel from the acceleration pump. Also reving from an idle is the same.
Don't worry about stuffing around with emulsion tubes unless you can get a lot of dyno time for free. Just getting your jetting closer will make a big improvement anyway, and F11's will be as good as the alternative F7's that you might be considering using.
I'm using 44idf's on my 1641cc engine setup as follows
55 idles
130 mains
210 airs
34 mm venturies
F11's.
My engine has been dyno run with an exhaust gas analyser and its right in the mark up to 6800 rpm. The distributer is a bosch 009 set to 32 degrees total advance, with high octane fuel.
In general what I have found with a 009 is set it to the max advance you can get prior to pinging, then back it back of about 2-3 degrees.
With a 1776 i'd suggest going back to square one with the following settings , and try changing things.
55 idles
135 mains
190 air correction.
F11's.
With 32mm venturies your limiting your top end RPM potential to about 5500 RPM on a 1776, but you will get better down low performance than with larger venturies. Keep the 32's if your engine isn't built to rev.
Have a look at the webber tuning technical document that you can download from
www.aircooled.net as well. It will give you a better understanding of how your idf's work at diferent RPM ranges, and how jettting overlaps.
I wouldn't recommend messing around with the air bypass valves unless the've already been messed with. Read the aircooled.net document, it will tell you how to set these up. But you'll need a balancing meter and a flow bench to do it 100% correct....
Good luck,
Ian.