As a longtime Pedal Steel Player I can tell you that what Mr Hullett says is right. Compression, Signal boosters, and overdrives are best before the pedal. Levels otherwise are really dodgy.
That's the main problem with the Line6 Podxt. The effects best put before the VP, unless you use the pedalboard or a volume pedal extension from the ShortBoard willl be after the VP, rendering the compressors and Overdrives pretty useless for controllable performance levels.
The best Volume Pedal I've found is the Infrared Hilton Electronic. The one Goodrich "copied" lately. When I tried it, and found the signal improvement, and level tone response it gave me, my 25 year/couple thousand gig used Ernie Ball became a spider house in my war room. Darn near all the steel players I know that have tried them do the same thing. the profile is much lower, even on the 'full sze model".
Now that I'm diving back into the Tele, I'm faced with a similar situation, but more need for a good compressor and overdrive. Being sold on the Podxt, I'll just have to have separate Pre-VP comps and ODs if I want to use them. (I wish someone would put together a Midi-type separate VP.)
(VPs aren't used as much as people think with PSGs, and with guitar I hardly use it at all. As Mr. H noted they are best used to sustain the notes longer. When I hear fellow guitar players "swell" chords and wobble them around to "replicate" pedal steel sounds, with few exceptions, they are imitating lousy pedal steel players.. (JMHO))
-Sometimes at my age I run out of adrenalin, but I've still got plenty of gall.- Me-
-Some people play music out of love; Some for money.
Myself, I play mostly out of Pure Spite...- EJL-