The following is about as much as I can simplify qi (not the actual formula for the real thing considering instant quanta producers, it does come close enough however):
Take the total quanta cost of all cards in your deck (by element), substract all quanta your cards can produce instantly (eg. 2 for each element other than entropy for supernova, 1 per upgraded pillar etc.). Then for each 7 remaining quanta cost of each element (rounded up) pack at least an amount of pillars/pends etc. that average a quantaproduction of 1 per turn if they were all in play at the same time.
In praxis this means 1 pillar, mark or 2 pends from the element (or any 2 pends if your deck mark matches the element, 1 if both are the same) or 4 quantum pillars per 7 quanta required (rounded up).
I chose 7 for maximum allowed qi, because even slow decks that take their time usually produce about that much quanta
Simple enough for someone Id expect to be favoured in a tourney environment, but not necessarily simple enough for me to want to require it as entry requirement for anyone that wants to participate.
*damselfly, gemfinder, brimstoneater, ray of light and devourer would count as pillar for the purpose of this calculation.