Trying to add different Nozzle Sizes

[4truemodels]

Hi there!

I've been exploring the Prusa Control folder in order to check what files should be changed so more Nozzle Sizes would appear to be selected.
Prusa I3 MK3 use a standard E3D V6 hotend, so more nozzles different from 0.25, 0.4 and 0.6 can be easily installed. However, as Prusa Control has no option to select those nozzles, we all are forced to use different softwares less final-user friendly than this.

I've tried changing the printers.json file from data folder, adding the following lines:
"0.8mm": {
"first": 0,
"sort": 4,
"name": "0.8mm",
"label": "Nozzle 0.8mm",
"parameters": {
"nozzle_diameter": 0.8,
"perimeters" : 2,
"support_material_contact_distance" : 0.35,
"external_perimeter_extrusion_width": 0.78,
"extrusion_width": 0.85,
"perimeter_extrusion_width": 0.83,
"infill_extrusion_width": 0.87,
"solid_infill_extrusion_width": 0.85,
"top_infill_extrusion_width": 0.77,
"first_layer_extrusion_width" : 0.83,
"support_material_extrusion_width" : 0.75,
"support_material_xy_spacing" : "150%",
"retract_lift": 1.0,
"extrusion_multiplier": 1.05
}
},

I've added these code lines just after "0.6 mm" within "i3_mk3", exactly in line 306 and before "default" that ends the code. That didn't work as there is no changes in the Settings tab of Prusa Control, no "Nozzle 0.8mm" appeared in the list.

Can you tell me what else should I do to add some other nozzles sizes like 0.8mm to this software? Thank you!