Means Go Loose Deuce, it is a pairs call to generate at /least/ one equivalent turn radius in a more or less bilateral split. There may be some lead/trail (300-400ft) split so the wingman can track the leaders moves from 'the corner of his eye' and their usually is some altitude separation for a variety of reasons. Again, formation element selftracking (you can use crossover as well as lead-lag TAC Turns), AAA/SAM fuzing and tap-bounce warnings from disadvantaged sun angles (the 'hun in the sun').
It is also a doctrinal tactics system, similar to 'leader leader' as practiced by a few successful souls in WWII. Wherein you've got maximum eyeball search coverage and the potential for section 'lead' to change to the engaged/advantaged side that acquires first is fundamental to faster, slicker, (supported) attacks.
Absolute Spacing depends on who you ask, in Vietnam the USN spacing was 6-9K feet which is essentially a turn plus half a 9's (Sidewinder) envelope.
USAF doctrine, which was based on the /moronic/ 'Fluid Four' (four aircraft, one lead-shooter), was between 2,500 and 3,500ft,
which is roughly /half/ a turn radius.
Especially at higher altitude it is even less.
Since the outside man in this pigs parade was in severe trouble in terms of reacting to a sudden break and because the wingmen in general were often less than helpful for training and deployed-experience reasons, it was normal to bring them in even tighter to 1,500'. At this distance they are 'welded wing' which goes beyond useless to tactically criminal.
Something which the USN proved, TWICE, with Crusader ACM deployments to USAF bases in SEA. 2 vs. 4 and the four F-4C/D/E never stood a prayer vs. the two F-8's.
With AMRAAM and JTIDS/IFDL and Supersonic Cruise bad formation consequences can hardly have gotten any 'better'. Spacing is likely now closer to about 10nm, or more.
Card I'm not so sure about. I /think/ it is typically a route formation and often used at low level with a four ship at the corners of a rectangle with about 6K feet on each side and as much as 2-5nm in trail. If you play poker, solitaire, whatever, think of the way the value markings are at each corner of each 'card'.
It keeps everybody out of each others ground tracks (again popup threat overfly as well as nav safety reasons at waypoint turns) and gives a measure of cover against an air-threat by allowing the outside element to turn in to cover his section lead (or vice versa) and the trailing section to cover the lead section of the flight.
In the early 80's 6 Jaguars bagged two Red Flag F-15's that dove on an extended card formation with the trailing elements outside the radar scan of the Mighty Eagles.
Shocked the Heck out of everybody but the Brits were awash in Beer at the O-Club that night...
'Simulators' typically make NO acknowledgement of the MASSIVE spacing necessary to both survive and /employ/ multihundred feet per second jet aircraft in the missile age and so are next to worthless in their 'formation' commands (which carries right on into Wingman AI and so forth).
WWII is little better.
Don't worry about it much, 'enjoy the game'.