I have fleet troop loadout set to:
Special Forces 35%
a fleet consist of 4 troop transports (4x600 space) and this loadout according to fleets screen, should load:
4 special forces
a planet from which I'm attempting to load troops has more than 30 Infantry units only. when I CTRL right click load troops the feet will fully load 24 infantry units.
Isn't a fleet supposed to load only 4 units?
Last I checked, transport fleets would pick up a force as close to the specified loadout as they could from the units available on the planet, and after that they'd fill out as much of their remaining transport capacity as they can with whatever ungarrisoned troops were available on the planet (within the limits inmposed by the game system; you can't split units across multiple transports). I think if you automate the fleet and leave it idle, it should eventually pick up something closer to its specified loadout, assuming those troops are available, but I'm not sure about that as I don't automate transport fleets.
Infantry and special forces take 100, armor takes 200, and planetary defense units take 400 transport capacity. Note that the troop loadout screen seems to think that special forces take 200.
As far as the transfer troops question goes, I don't know, but I suspect that any time you can transfer troops (but not characters) to a transport outside of the system in which the troops are stationed, you're encountering a bug.