General rule of thumb is one-size smaller Jet for each 2,000 ft of elevation gain. The 1.32 primary and 1.80 are probably a good place to start if you're only going to see 6K ft and above.
No idea what you're looking at for an Idle-up Solenoid that's $400, but that's crazy. Any VSV that's normally closed will work - you only want to apply vacuum to the Idle up dashpot when A/C is activated, and the signal to switch the VSV on or off will be controlled by the A/C amplifier.
There are many that will will work - Usually the difference is just the connector style (always two-pin) and if it has a bracket or not.
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Pretty sure this is the right connector, but you'll have to verify
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