Can I start out by saying that over the last few decades, I have fitted
quite a few of these 'FOBO/FOBO2' type TPMS kits to many Spyders &/or Rykers, and many similar TPMS kits/sensors to even more other vehicle types, and I can say that I've
NEVER had any issues simply screwing the FOBO/FOBO2 sensors on instead of the original valve caps onto the OEM valve stems, regardless of whether they were short or long; not on an F3, not on an RT, not on a Ryker, nor any other motor vehicle, and very, very few of the owners of said Spyders/Rykers/other vehicles/vehicle types have ever come back to me and said they've caused issues later! It's gotta be an absofreakinlutely
tiny percentage of owners who didn't just get them fitted and then use them, basically trouble free from the set to!
That said, waaaaay back in the early days of these sorts of sensors, last century some time, I
DID have a few 'Tyre Dog' TPMS sensors (which are, for all intents and purposes,
EXACTLY the same as the FOBO/FOBO2 sensor, right down to internal components being fully form, fit, and function inter-changable!) in a few very rare and quite specific usage instances, which had issues with the sensors being torn off
LONG valve stems, both rubber &/or metal, but only when they were fitted onto long valve stems installed in exposed places on 4WD wheels that were being used in deep, loose, rough stuff. But AFAIK, none of that sorta usage applies to the pretty well recessed and protected Spyder/Ryker valve stems &/or their main usage, where sometimes, you might even need to leave the locking nut off the sensor so that it'll tighten down on the
short valve stem sufficiently to work, in which case it works admirably! And just btw, I haven't yet found a valve stem that was too short to screw a FOBO/FOBO2 type TPMS Sensor onto either - if it's long enough and the end of the stem is exposed enough for anyone to physically reach it and screw a valve cap onto it, then it's long enough to accept a FOBO type sensor!
So Pete, and I truly mean this in the kindest way, but I reckon that you should
simply STOP reading about all this, AND JUST DO IT! You're chasing your own tail down a rabbit hole of your own making, finding all sorts of crap that, if you eventually get to read right to the end of said rabbit holes &/or the vast majority of threads about this stuff here, you'll find that pretty much none of it
really matters all that much &/or has any
real impact on what you're trying to do!!
So go on, JUST DO IT! 
You know you want to, so stop trying to find &/or convince yourself that it's really any harder than buying the FOBO/FOBO2 or whatever kit, taking the sensors and screwing them on. Sure, you might need to decide whether to bother with the locking nuts or not, but few have ever lost a sensor due to the lack of one of those nuts, and apart from making that decision, it truly isn't all that hard! And in the rather improbable event that you do end up having any issues, you can report back and be the first to actually
SHOW us here what those issues are!
But you don't need to buy trouble for yourself before any of it has ever happened, so don't sweat the small stuff; and btw, it's really
ALL small stuff! Just Sayin'
And then, you can...
'RIDE MORE, WORRY LESS!' 
Ps: Personally, I wouldn't even bother with the 'T' valve stems! Once you've got FOBO or any similar TPMS fitted onto the OEM rims/valve stem with any reasonable quality tire, you most likely aren't going to need to get down there to check the air pressure all that often anyway; nor are you likely to need to physically access the rear valve stem anything much more than
maybe once a season or so; and for the cost, time, effort, and trouble you'll be causing yourself simply by having those 'T' valve stems fitted, let alone all the angst
you are putting yourself thru stressing about all this irrelevent crap, I reckon you'd be
FAaaarrrrr better off without them! Just get the new tires and FOBO/TPMS fitted & set up on the OEM valve stems, and then truly...
just
'Ride more, Worry Less!' 
