I have started building a vac, but not got around to finishing it yet...
I have been on a few swarm and colony collections now. For a swarm I have managed so far to get away with a five frame nuc. For colonies, they vary dramatically. One I managed to fit in a single nuc. The one that OzBuzz and I pulled out of the chiney took 2 nucs to fit it in.
I went on a collection yesterday that the brood took up an entire 10 frame deep on their own. I'm going to put the pics in a fresh post, but essentially I could not fit all of the bees and brood in one 10 frame box.
My suggestion is when you go on a swarm collection take a nuc and an 8 frame (or 10 if that is what you use) and pick the box that fits the number of bees the best.
On a colony collection take a nuc, if it is small. If it turns out bigger have a deep with you. Be aware that if it turns out to be a monster you could need 2 deeps. If you have to remove walls or other obstacles to get to the comb you will not know ahead of time how big it is. Be prepared, take a range of boxes.
If it is a feral colony removal, be prepared for a long day. They can take anything from an hour up to 6-7 hours to complete.
And where do they end up after I have collected them? I have given most of them to beginners as their first hive. 2 of them last year went to a semi commercial/large hobbiest who had lost more than 1/2 of his hives to a crop spraying, but I prefer to donate to begginers.