Pinch-proofing tire installation, aka shake and bake:
2 tubes. 1 gallon Ziploc bag. 1 container of talc powder, preferably unscented. DO NOT USE CORNSTARCH baby powder!!!!!
Keep the valves capped, put tubes into Ziploc bag, add couple teaspoons of talc. Zip the bag with some air trapped inside for the powder to flow free around the tubes and shake.
Talc will stick to the tubes, add little by little until tubes are silver in color and stop consuming talc.
Install the tubes just like normal.
Wipe talc fingerprints off the rims, tires, frame, kitchen ceiling, wife, dog and goldfish. Yeah, it is THIS messy.
Now the tubes and insides of the tires are slippery enough not to worry about pinching. Ever.
Side benefit - lower rolling resistance,
Good Luck
SF