GET automation - Schedule.Create fails & force to factory reset

Hi

I'm trying to "automate" the management of scheduling rules for an irrigation system via http:

With gen1 devices it were very simple:

http://192.168.33.127/settings/relay/0?schedule_rules=1000-0123456-on,1012-0123456-off,1400-0123456-on,1012-0123456-off,1404-0123456-off,1800-0123456-on,1012-0123456-off,1404-0123456-off,1810-0123456-off

Now, with gen2 devices should be easier, but I couldn't find the proper way:

For example, using schedule.Create, and @sunrise+1h59m and the web interface it seems to work:

http://192.168.33.127/rpc/Schedule.List

{
    "jobs": [{
            "id": 1,
            "enable": true,
            "timespec": "@sunrise+01h59m * * SUN,MON,TUE,WED,THU,FRI,SAT",
            "calls": [{
                    "method": "switch.set",
                    "params": {
                        "id": 0,
                        "on": true
                    }
                }
            ]
        }
    ],
    "rev": 26
}

but, if I use the rpc interface to add the schedule (previously I delete all using Schedule.DeleteAll):

http://192.168.33.127/rpc/Schedule.Create?timespec="@sunrise+01h59m * * SUN,MON,TUE,WED,THU,FRI,SAT"&calls=[{"method":"Switch.Set","params":{"id":0,"on":true}}]

I get

{"code":-103,"message":"Invalid argument 'timespec': Failed validation!"}

Also, the rpc interface for Schedule seems unstable... it's force me to factory reset the shelly plus 1 to get it work again... seems some kind of problem managing the scheduling list via rpc interface.

I'm open to suggestions

Thanks in advance !!!!