Just to add further comment.
Wherever I go pballing I take my 232 bar dive bottle with me, just in case the site has a problem, and it has indeed helped me out where the site fills were far short of 3000psi. Deffo a worthwhile investment Iongale.
As for your marker air system, deffo go for the fibrewrap 1.1L 4500psi if you can afford it. If your on a budget, then LiPS will sell you a pure energy ally 0.8L 3000psi for about £43 + P&P, which will get you by until you can afford to upgrade.
Most walk-on type sites do not fill over 3000psi anyway.....
Note, when my Ion was stock I got about 500 shots from a 0.8L 3000psi. I've now got a QEV, firebolt, Lucky Stage 2, blackheart board, freak, allowing me to lower my dwell substantially, and I can now get about 700 shots. Still have ran out of bloody air on the odd game though!!
Hope helpful.