I will likely order both sizes but for interests sake emarine says 1/4" for a 1 inch shaft as per below:
Available sizes - 1/8", 3/16", 1/4", 5/16", 3/8", 1/2", 5/8" - accommodate most power and sail boats. Other sizes available on special order.
Buck Algonquin Bronze Packing Boxes are usually the following sizes and take the following packing size:
Shaft Size
3/4"-----
7/8"-----
1"-------
1-1/8"---
1-1/4"---
1-3/8"---
1-1/2"---
1-3/4"---
2"------- Packing Size
3/8"
5/16"
1/4"
3/16"
1/4"
5/16"
1/4"
1/2"
3/8"