Brian,

By our size chart you would be a 54cm.

But be advised on the tire sizes that you listed that 700×2.1 is at the very limites of what Flaanimal fits. It is okay to run in the dry but in mud / clay you will rub. Nothing larger than 700×2.1 will fit the frameset and honestly the bike rides better with 650×2.3 than it would at 700×2.3 if it could even fit 700×2.3

On a 4.1 a 45c wouldn’t fit under fenders especially with Spork 1.2. You would need to size to 38-40mm at 700c on a Flaanimal 4.1

Looks like Velo Orange has the only other option for larger 650 tires. Unfortunately you will need to drop to a smaller tire on 4.1. 42mm Max.

A small flathead screwdriver helps tremendously with seating those in place.