Quick & dirty conversions:
Plato is just gravity units changed by a factor of 4. So 15 Plato is about 15x4=60 GU or 1.060.
Kilograms are heavier than pounds by a factor of 2.2. So 20 kg = 44 lb. Or just multiply by 2 then round up a little extra. Or going the other way from pounds to kilos, cut in half and round down a little extra.
Liters are just almost the same as quarts. Not much difference there. A little less than 4 liters per gallon, because liters are just slightly bigger than quarts.
For C to F conversions, you need to keep in mind that they are different by a factor of 5/9 or 9/5, depending which way you go, but there's the extra 32 F = 0 C thing that you have to add or subtract also. So...
Switching from C to F, divide by 5, multiply by 9, then add 32.
From F to C, you need to subtract the 32 first, then divide by 9 then multiply by 5. Difficult to do in your head, but not too hard on a calculator.
As another swag, each degree C is almost 2 degrees F. So going from 65 C to 66 C, that's a change from 149 F to 151 F. Each degree C is worth 2 degrees F, approximately. Or 9/5 to be exact.
Maybe this helps, maybe not, but it's documentation of the way my own brain thinks, so maybe it will help out somebody who thinks in a manner similar to the way I do.
Cheers all.
