REACTOR...Need advise!

Hi guys... I looking to create a reactor that wiil do the following:
1-Modify the layout name. It wiil add the drawing name(not the file name) + the revision#. All those information are stores in my titleblock as attribute. So, it as react when I'm modify the attributte and when I switch to the layout.
VLR-layoutSwitched) (I dont know if there's on for attribute)

2-Modify an attribute base on the file name. I can't use rtext because I already have tons of files that have to be updated.
Obviously this as to be done when I open the drawing.
vlr-documentBecameCurrent)

A will use my AcadDoc.lsp to store those reactor. The attribute tag prompt are exactly the same on all drawing I have to updated.
The first reactor as to look two attribute's: DWG_NAME (CELT-01) and CURR_REV (4). Base on that he create a layout name (CELT-01_04).
The second reactor's as to updated the DOC_NAME attribute. (JSCELT0124.dwg).

Should I start my reactor by looking for a block than finding the right TAG PROMPT....

(vl-load-com)
(setq ss (ssget "X" '((0 . "INSERT") (66 . 1)))
)
(setq cnt 0)
(repeat (sslength ss)
(setq ent (ssname ss cnt)
cnt (1+ cnt)
)
(setq BlkObj (vlax-ename->vla-object ent)
AttObj (vla-getAttributes blkobj)
AttLst (vlax-SafeArray->List (vlax-variant-value AttObj))
)
(foreach n AttLst
(if (= (vla-get-tagstring n) "DOC_NAME")
(vla-put-TextString n (getvar "dwgname"))
)
)
)

then, I'm not sure on where should I go...

Any advise will be greatly appreciate!
Simon