Hi Marco,
FT1 is out of production so you will need to look if someone sells it.
I have a FT1x and bring it on every activation. APRS position beacons are great for chasers to estimate how much much time I need to the summit.
I have spotted to APRS2SOTA but the entry of the details is a bit inefficient using the rotation dial or the keypad (like on old Nokia phones).
So yes it works. Is it fun. No
Here a video how to edit and resend a message:
For me the last resort in case there is not even phone reception to send a spotting SMS.
The other alternative would be to use APRSdroid to generate the audio and send it via a non APRS handheld.
This was discuss here recently.
Or the Pico APRS system:
73 Joe