1)
Here it says that each was five Amos tall. In Melachim II, 25:17) it says that it was three Amos!
1.
Refer to Melachim I, 7:16:4:1-2.
2)
How were the "Sevachah v'Rimonim" on the crown?
1.
Rashi: The crowns were like two bowls. The bottom one faces up (like normal); the top one is inverted and covers it; it is called Sevachah. Pomegranates are inserted in chains. The two ends of the chain are tied together on top of the Sevachah, where it is narrow. [The chain] descends to where the Sevachah sticks [to the bottom bowl], where the crown is widest. The pomegranates cover where the mouths of the bowls are stuck together.
2.
Refer to Melachim I, 7:17:1:2, 7:18:3:1-2, 7:18:4:2-3.