Just noticed this....hope this helps....two things:
1. The 8mm thread in the middle of the outer axle is to pull out on the stub while putting on the circlip....but not always...as the pirates say, "There be dragons here!".... There is an improved spindle that has a brass bushing...used for full-time 4WD. If this is actually an FJ60 knuckle, it won't have that bushing. This outer hub is more like FJ80 or RN/VN ifs front ends.
2. The only reason for the clip is to prevent inner axle retraction while turning sharply under power. Many LandCruisers ran without the C clip their whole life (some brands of aftermarket hubs wouldn't accept it). The only time I ever saw a problem was when plowing snow, in the spring, when the parking lot was starting to melt clear (good traction) and the driver was straightening out from a hard turn while pushing heavy wet snow around the back of the building. The end of the axle would "walk" into the outer hub while turning (more than in your pic) and then need to extend back as the wheels straightened. The spline load would be so high that the axle couldn't walk in the outer hub and it'd blow the studs and outer hub into the nearest snow bank.
The Birfield will find it's own "best length" and be fine without the clip, unless you'll be plowing snow around sharp turns.
I'm nervous about your "reseal" comment....there shouldn't be any gear oil at this area. The FJ knuckle uses wheel bearing grease, and the axle seal is inboard (the square plug on the knuckle was NOT to fill with gear oil...it was to inspect the grease during military maintenance). If the diff level is run too high (should be about 10mm BELOW the bottom of the fill hole...max), the oil will get into the knuckle, thin out the grease, get into the wheel bearings....thin out the grease....smoke the bearings during continuous high speed cruise.
