Having the throttle with some mechanical interference internal to the pump doesn't sound good at all. Sounds like you might have to take the pump off the engine, open the inspection plate and see what could be the problem. If the CSS came completely out, a linkage may have come undone or it's grossly maladjusted from your re-installation. The distance from the top of the pump to the bottom of the "can" on my pump is very small, maybe only .25". You'll need a very thin wrench (you can grind a junk wrench to the required thinness) to tighten the CSS locknut. I would guess that it's probably not too serious to fix, but it may have to come off the engine to see what's wrong.
Do you have Wes Ingram's SPICA manual? If not, you should get it. IAP sells it. Also, check out Wes' site
www.wesingram.com
A dummy TA is easy to fabricate - just file down a flange like the regular TA and drill it, then tack weld or epoxy a nut. Then just use a regular bolt and locknut to set the 29mm length.
If you have the pump off the engine, it's probably worth removing the TA as well and test it in a pan of hot water for specification.
The CSS does have a specified standard height from the top of the pump to the bottom of the can, however, I don't have access to my SPICA manual right now. The following link has a SPICA tune-up procedure that also covers CSS adjustment. However, if you've got a bad link in the pump, I probably won't help.
I've got a dummy TA that I can loan you if you need it. I've also got a spare pump from a '77 if you need it for troubleshooting.
http://www.alfaclub.org/techstff/tunespca.htm
When I get to my car and SPICA manual next Tues PM and , I can take a measurementof the exact adjustment on my pump, check the manual, and send it to you as a reference point for adjustment. Send me a private message if I can be of any more help.