Diameter and beam differently; Compatibility with halogen transformers

Have after the positive reviews my previous halogen spotlights (Osram, 38 °, 30 Watt) to replace.
Basically pleasant light of LED lamps, but:
1 - flicker with my 7 year old about transformers problems, if I only the LED spots insets (below any minimum load for the electronic transformers, comes when a halogen lamp is added)
2 - The light cone is despite identical angle specification (38 vs 40 °) different: while Osram halogen illuminate very moving terms, the Samsung LED lamp combines the central cone stronger and know a distinct yellow discoloration at the edge of the light cone. That bothers me greatly for the illumination of pictures and falls unpleasantly on the wall, if not all bulbs are identical.
3 - the diameter is about 1-2 mm higher at the front than halogen bulbs - fits with me only with slight force into the sockets.

Conclusion: Be careful with older halogen transformers, not always compatible. To check on the meaning of the other light beam to be clear and sufficient clearance of the old halogen bulbs in the socket before replacing.