start with preparing a tech rider. Tell them what you need(what sort of amp, amp with effect loop etc), to use with the rack stuff.
If possible, communicate everything before the gig and confirmed that theres arrangement done to facilitate the use of the rack equipment.
A proper gig locally, usually requires the band to submit a tech rider before hand, to inform of organiser what they need and organiser side, will arrange and prepare the gear accordingly, within their reach
if no tech rider and stuff or proper communication before hand, at least on the gig day itself, there will be soundcheck(if the gig you play has no soundcheck even. Heh, forget bout getting a decent sound overall or simply to rock out...). Make sure that within the time frame given for soundcheck, do whatever its possible for the geetar and rack stuff to be able to produce sound and overall playing with the band
as long as everything within the rack gear itself, is connected before hand, when at sound check, all that needed is plugging geetar into rack, and output of rack to amp. Its prolly good enough to save some time for individual instrument line check and overall band mix.
If the soundcheck duration is short, make sure everything is connected(rack), setting tweaked/confirmed before hand. Reach place, just need to connect geetar, amp, tweak a bit on volume/gain/mix etc, tune and start the line check.
If soundcheck timing is long, same as above. Still do everything before hand and save the time for other things.
imho
