Bangle GPS Power management

Had a closer look at the code and the datasheet.
I might be a bit further along on answering my original question.
I dont have my watch yet so cant really test

/*
UBX-CFG-PMS - enable power management - Super-E
period and ontime are ignored and set to 0 in 1hz mode

See: UBX-13003221 - R21 page 243, for format of config message

*/
function UBX_CFG_PMS() {
  writeGPScmd([0x06,0x86, // msg class + type
         8,0,//length
               
         //v0,  1hz     period            ontime       reserved
         0x00,  0x03,   0,        0,      0,      0,   0,      0  ]);  
}

/*

UBX_CFG_2MIN - enable power management, Interval type: 2 min period (0x78), 7s On time
FIXME: need to enable Enable waitTimeFix feature ?

See: UBX-13003221 - R21 page 243, for format of config message

*/
function UBX_CFG_2MIN() {
  writeGPScmd([0x06,0x86, // msg class + type
         8,0, //length
         //v0,  interval     period            ontime           reserved
         0x00,  0x02,        0x78,        0,    0x07,     0,    0,      0  ]);
         // the values are little endian, least significant byte first
}

There are some example interval setups in
section 13.2.4.3 of the datasheet:

Use update periods of 30 minutes

Scenario: Get a position fix once every 30 minutes and acquire a fix needed for timing products.
Solution: Set mode of operation to PSMOO. Set updatePeriod to 1800 seconds.
Set the search period to 120 seconds. Enable waitTimeFix feature"