found four old Minco heaters (model HR5494-106) (from 1995) .  This type with 106 Ohms is not in their system anymore.
But corresponding to their data the maximum current for this type of heater is about 7.5A. So driving this heater with 24V would give us 5.4W of heating power beeing well below the limit. Using the standard power supply for heating refcavs we can get even more power. Due to the age (14years!) the adhesive back is not sticky anymore so i will use aluminum tape for first tests.

Model
HR5494	Silicone Rubber heater : 4.00" x 8.00" (101.60 mm x 203.20 mm)		Effective Area : 30.3 in2 (195.484 cm2)   Lead Gauge : AWG 24   Max. current : 7.5 Amps
Configure this model in Kapton
Application Information			Actual Current : 0.21 Amps
Operating Temperature : °C   Heat Output at Volts
Resistance in Ohms
378 • 1.52 Watts → 0.05 W/in2 (0.0078 W/cm2) 189 • 3.05 Watts → 0.1 W/in2 (0.0155 W/cm2) 114 • 5.05 Watts → 0.17 W/in2 (0.0264 W/cm2) 55.1 • 10.45 Watts → 0.34 W/in2 (0.0527 W/cm2) 37.6 • 15.32 Watts → 0.51 W/in2 (0.0791 W/cm2) 26.3 • 21.9 Watts → 0.72 W/in2 (0.1116 W/cm2) 13.1 • 43.97 Watts → 1.45 W/in2 (0.2248 W/cm2)
Leadwire Length
Units	Inches    Centimeters
	Up to 12" included in price. Over 12", up to 80" add $3.00
Heater Backing - Based on Operating Temperature (see above)
Type Temperature Maximum Allowable Watt Density A No Backing -45 to 235° C         Installation options for unbacked heaters     #20 Stretch Tape -45 to 200° C   1545.3 W (51 W/in2)     #6 RTV -45 to 235° C   887.4 W (29.3 W/in2)     Factory Vulcanized -45 to 235° C   1656.4 W (54.7 W/in2) B #12 PSA -45 to 177° C   1292.4 W (42.7 W/in2) D 0.003" Aluminum Foil Backing -45 to 235° C     E Foil with Acrylic PSA -45 to 150° C   1100.4 W (36.3 W/in2) F Foil with #12 PSA -45 to 204° C   1100.4 W (36.3 W/in2)
UL Component Recognition
	Check to have heater marked for UL component recognition
Part Number (as configured):   HR5494R114L12B