Using CL to call RPG pgms

Hello!

I have almost 1,5 year expirience in ILE RPG IV and now I realized that 
almost evry RPG pgm I've made needed additional CL pgm that shold prepare 
LIBL, clear output PFs and perform similar actions after pgm finises...

I'm wondering would it be to complicated to perform all this within RPG 
pgm (for example in separate module or subprocedure) with use of different 
APIs (QCMDEXC) and explicit file OPENing. (inexaple. if I define file in f 
spec with USROPN keyword would I get err. message if file is not in LIBL 
on pgm start).

I suppose there exist some actions (as file override options for RPG pgm 
that will be run) that must be defined in CL??

What is better practice? It's probably metter of programers style but it 
would be nice to know how other programers do that.

Is there any situation when this start actions should be performed in CL?

And at last, I realized that all the time I was repeating one error: when 
I compiled CL I got OPM CL that calls ILE RPG, what makes my pgms runs in 
different ACTGRPs and in case of unhandled exceptions I get inquiry msg 
for RPG (when its ACTGRP scope ends) and same inquiry for default OPM CLs 
ACTGRP.

Should it be enough to create CL source with CLLE attribute and compile 
ILE CL it with ACTGRP(*NEW) or some named ACTGRP and copmpile RPG PGMs 
with ACTGRP(*CALLER)?

Is there some good literature about ILE CL and some rules that should be 
respected when use it to interact with ILE RPG??

I hope that questions aren't  too wide :)

With regards,
Igor Bešlić, dipl. ing. rač. 
VOLKSBANK d.d.
OJ Informatika
Zelinska 2, 10000 Zagreb
tel: +385 1 4801 895