Clash-of-clans – Eligibility of war loot

The system will try to match your clan into the highest bracket based on available members, and remember that clan war team sizes are always in multiples of 5.

When a member is "ineligible for war", they're not considered at all when it comes to matching up for the clan war.

In your example, you have 2 people ineligible and 40 people that are eligible. The system will take these 40 eligible people and start a 40v40 war with 2 spectators. If you had 3 people ineligible thus making it 39 people that are eligible, then it would start a 35v35 war with 8 spectators.

Nope.

Whenever you receive loot, you only receive the full amount (if your resources have space for them all), or up to the amount to entirely fill up your resource tanks. The rest is lost into the abyss.

As for upgrading your resource tanks/clan castle - Overspilled resources (that amount that couldn't fit into your already-full resource buildings) cannot be recovered.

All I can suggest is that always have a big-enough resource storage or: make sure you can house more resource than you can think of ever getting.

(My resource tanks always get filled up by the harvesting of a single full resource collector. Basically: My resource tanks can hold one third of what I harvest.)