T5 Trans Swap into 66 C10 - couple questions

[jocko]

Howdy Truckers,
Have a T5 that I am swapping into my 66 C10. As expected, the input shaft is too long, so exploring a couple options. I know I can have the input shaft cut down (and the splines ground down a bit, and the bearing retainer collar cut back a bit as well), but my main question is about using the Hamilton adapter plate http://hamiltonintakes.com/products/...5-swap-adapter

A couple questions:
- Is this adapter ONLY for adjusting the input shaft length problem (or does it also compensate for a mismatch between the T5's bearing retainer collar diameter and the bell housing index ring opening diameter? (I THINK it is only for adjusting the input shaft length problem - i.e. if the T5 bearing retainer collar and the bell hsg diameters match - and then you can use the adapter.
Anyone know?

- if one uses the adapter - the splines, and collar are set back an equivalent amount relative to the insides of the bell hsg (i.e. throwout, clutch disk, etc). Since the adapter moves the whole trans back approx 9/16" (and therefore the input shaft does not need to be cut) - do the splines on the T5 shaft also move back the appropriate amount such that no splines need to be cut back? (I THINK this is the case - that they do not need to be cut, but not sure).

- Finally - the bearing retainer collar....
My old 3-speed's bearing retainer collar is 3+1/8" long.
The T5's bearing retainer collar is 4+1/2" long.
Difference is 1+3/8" approx.
The Hamilton spacer is 9/16" thick.
So - does the T5's bearing retainer collar need to be shortened?
If so, how much? My assumption would be (1+3/8" collar diff - 9/16" spacer)=13/16"...
Anyone know? Might be able to not shorten it at all, i.e. 9/16" spacer may compensate enough, but wnot sure. All things being equal, I think it should be shortened approx 13/16". Thoughts?

Appreciate the help folks.
jocko