The TFC-1000MSC has SC (square) connectors, so if you're using ST (round) termination, you must be using some sort of dongle or coupler between the ST jack on the patch panel and the SC fiber jack on the fiber converter, right? Is the 3-meter test fiber terminated SC-SC, or are you using an SC-ST dongle or coupler for your test? Are your old 100base-FX fiber converters SC or ST?
In general, fiber is fiber. We use both 62.5/125 and 50/125 for 1000base-SX connections have no problems with either (using LC or SC termination). However, this page notes that if you have to couple multiple fibers together, it's important that all of them be of the same type, or you can get light loss.
If you're using all 62.5/125, then it may be that your ST connectors are not designed to pass the wavelength of light used by 1000base-SX. If you look at the Wikipedia pages you referenced, you'll see that 100base-FX operates at a wavelegth of 1300nm, while 1000base-SX typically uses 850nm. I don't know if connectors even have such limitations or not, but I do know that ST is not commonly used anymore, and I've never seen it used for GigE.
Also, keep in mind that 100base-FX and 1000base-SX are not compatible. If you're only testing one end of a run at a time, you definitely will not get a link. Aside from the fact that the use different wavelengths, neither of them is 10/100 or 10/100/1000 auto-sensing. In my experience, this is not universally understood. :)
Given the precise hardware you mention I do not have anything to add that has not already been mentioned.
The idea of having two EtherChannels, one to each switch in the rack, per ASA could be simplified quite a bit by using stackable switches. I realize that if you already have the hardware this is moot - however it could simplify future implementations with a slight change to hardware acquisition.
The Cisco 2960S line (the latest model refresh in the Catalyst 2960 series) support stacking through the FlexStack stack module -- similar to how the 3750's are stackable with StackWise[+]. FlexStack and StackWise are not the same, but from an administrative standpoint they yield many of the same results. For those that don't want to plunge into chassis switches, Cisco's stacking capabilities on the 2960S's and 3750[V2,E,X]'s provide a handful of similar functions.
In this case specifically cross-stack EtherChannel can yield much simplification. With cross-stack EtherChannel it would be possible to configure a single EtherChannel from one ASA with one PHY interface going to the first switch in the rack and a second PHY interface in the EtherChannel going to the second switch in the same rack. Additionally, the switches in the stack (in the same rack) do not need EtherChannels configured between them -- as their inter-connectivity is provided via 2960S FlexStack.
FlexStack cables can be up to 3m in length -- depending on how close your racks are together you may be able to stack all four switches.
With multiple ASA's in HA the desired redundancies can be achieved with quite a bit simplified.
I bring this up because I have similar objectives you list met with ASA's in HA and stacked 3750X's at a few client data center sites.
Best Answer
That will support Gigabit Ethernet over that distance. However you need to check that the physical interface on the new switch transceiver matches your current transceiver (which is SC) and I suspect they won't match.
You can use this chart to help identify connectors, if you know the model of the Cisco switch. It's likely that it is using a SFP module.