Ted -
just typed a massive long reply and hit the escape key at the end killing the whole message - to make a long story short - you're fine.
When soldering leds - you'll be done in under
3 seconds with good flux.
You will grow to learn that the metcal tip is always 700 degrees, even under the worst load, and you can get by with a 600 degree tip as well. WEller/ungar irons vary their temperature based on load - metcal doesn't - that's the difference.
The exception to this is metcals long tips like the sccx45a at 19mm - i'd order 700 degree on this.
as for burning things - I personally use 600 degree tips - my tech. at work uses 700 degree tips - she has never burnt anything because the tip is in contact with the joint for 2-3 seconds and then done.
Finally - if you can't find the exact shape - I've bought an oversized tip from metcal - then stuck it in the bridgeport mill and made it more the shape I wanted. You can do this, but you need to realize that keeping that tip tinned and clean will be important.
As for coax (PL-259 connectors, etc) - I would have chosen the ssc-713A - with 7.6 mm between the tip and the heater (the heater is those double vertical lines before the barrel) - it will react VERY vast - your 717 tip is 10mm - still very fast, but you can shove the 713 tip in the hole on the pl-259 connector and get better thermal transfer.
While a weller/ungar may take 30 seconds to recover from being touched to a cold, large object (pipe, pl-259, etc) - the metcal will recover in 1-2 seconds max (usually 1/2 sec) - because of this, there's no need to oversize the heater in the metcals - a 600 degree tip will do most electronics (transistors, leds, etc) without a problem, and without you even knowing it's not a 700. But you spend so little time on each joint (2-3 seconds) that the 700 degree tips don't burn stuff up.
Also - metcal has 2 series of irons - the "economy" and "cost is no object" series - we're talking about the economy - the tips ARE NOT INTERCHANGABLE between the two series. - the technology and power are the same - the difference is stuff like the solder sucker (which uses a venturi vacuum to pull solder through the board from the back side!) and some really oddball tips (I'll have to post pictures later) that let you do some major rework on smt parts. If you are not designing smt yet, your metcal will do everything the other will for about 1/3 the cost. When the time comes to upgrade, it will go on ebay for a premium over weller - metcal anything gets massive bids on ebay.
email me direct - I don't always check every board every night - eb at hmmwv dot net