Reducing overall Tire Size?

[Desert Bred]

Hi. I have:

Front tires that are: 6.00 - 16

Looking at some used tires and rims that are: 5 - 14

Rear tires that are now 9.5 - 24

Looking to put 8.3 x 20


Does anyone know if this will work off hand?

Thanks for the insight.
DB