Ime 'pub band' venues don't have the capacity for worthwhile stage monitoring without causing an unholy mess out front, even with a stage. Vocal PA ftw.
So I asked OP what his average means.
Long before internet forums I must have picked up on the essential truth from one of the old pros I got to jam with as a beginner.
In my first rowdy band with my pride and joy Trace rig being hard to hear over the stupid loud guitarist I drew a line in the sand and the guitarist was forced to pull his head in.
The line I drew was where the speaker didn't get any louder despite increasing the master and backing off a tad for good measure.
Ten years later I learned about ohms and watts and volts and sensitivity and it made little difference to operations aside from the addition of a high pass filter.
Off topic but one of the most entertaining cover bands I ever heard played everything funky. All the usual suspects, no matter how non funky the original, got made into funk without sounding wrong. That's not easy!
An outstanding example of the kind of lowlife that gets up to that sort of thing story...
A few years ago Christchurch had a bad earthquake. The worst building failure was the near total pancaking of a reinforced concrete multistory office building. Something like 3/4 of all the deaths in the quake were in it.
The investigation turned up that the supervising construction engineer was a con artist. Had the building been built properly it should have stood up but they couldn't prove it. As far as I know the guy never even went to court but he lost his job as a ''helicopter maintenance ''engineer'''' in Australia. Some mothers' children....
A spike is very unstable rotationally until you add a wing to brace yourself into. That's why the tripod is the usual goto stand.
Your original plan to spike it between your feet and pad it against the chair would work but it would put the instrument quite vertical and too far forward unless you can sit up and balance on your haunches?
The trick is to put the heat shrink on the wire before soldering together ( DOH!!!) and not get it all so hot that the heat shrink goes off before you slide it onto the joint!
Tinning the wire ends goes a long way to making it quick to get a joint.
Remember that solder flows towards the heat.