M&F about DryBox,
M1: Silica Gel turns pink in one or two days.
F1: Silica Gel will not turn pink in a "Closed" dry box. Even if it does, the moist level in the dry box will not increase as long as the box is "air tight". Silica gel will be less effective when the drybox is open too often. Put a hydrometer permanently inside the drybox, check its meter value 4 hours after the box is "closed". If the meter reading did not go below 60%, replace with new or fresh recycled silica gel and repeat check again. If the moist level increases while the box is "Closed", the box may have a faulty seal or it is not closed properly.
M2: You need an microwave to recycle silica gel.
F2: All you need is a $30 oven style bread toaster in the nearest NTUC. You can use it solely for baking silica gel. The toaster will come with an alluminum tray. Fill the tray at the depth of 1 silica gel. Power on the toaster for 2 minutes and you should see water droplets on the toaster window. Remove the "BLUE" silica from the tray and store in an air tight container. You can accumulate all used silica and bake them all when you're free.
M3: How much silica to use?
F2: Use a hydrometer to check. Put any amount of silica gel into your drybox. Monitor the meter reading after 4 hours, if it goes below 40%, its too dry. Open the box and let the meter reading reach room moist level. Place new silica with less quantity into the box. Repeat the process until the meter stable at 40-55%. Note down the amount of silica use with a measuring cyclinder and using it for future reference.
M4: Dry cabinet is "better" than Dry box.
F4: That depends. If one of the lenses is infected, fungus spread is isolated only to the dry box which it is kept. Unless you're rich enough to own many dry cabinets, you can't beat the dry box for this.
Dry box store away easily, it don't need to be tie down by an electric cable. You don't have to worry if the dry box is damage during a power trip.