I did quite a bit of testing on mine. It's a 68, with a 71 704 carb, choke stove. Blocked the driver side crossover passage so exhaust can still get to the choke stove .. but yeah, it's not forced through. Had to adjust the choke link a bit more than normal, but after an extra five minutes of warm up the intake is warm enough to fully open the choke.
I also run an OEM air cleaner with the pre-heater installed which helps with warm up, and also when intake air drops below a certain temp at any time.
I don't know about fully filled crossovers as I've never had them ... but my setup seems to be a good middle ground. I'm more likely to be driving in 80 degree weather than 50.
Kenth ... you live in freakin Sweden
Of course you need an operating crossover, it never gets above 50f there
.