I have a Record Power DX 1000 vac and clamp the 100mm hose under the piece i am sanding this catches most, i have also got the Record Power AC400 have this running all the time i'm in the shop and leave on for 1 hr after i leave shop ( shop 16X 10 ft), i have noticed a big reduction in airborne dust since i set this up .
we have a Jet AFS 500 at work which does the same job as my record power, but costs about twice as much, and 5 year warranty on RP stuff.
we had Mike Hanbury demo at our club a couple of months ago he wet sands with a homemade sanding paste 80% liquid paraffin and 20% beeswax ( heat to melt wax in paraffin and store in airtight container), if abrasive clogs a quick brush with a stiff brush does the trick and the 'slurry' it produces just falls to the ground, not found sanding takes any longer really, just a quick brush of abrasive every now and then, been sanding with this for a couple of months and dust is minimal, and the little longer may take is offset by air quality, sanding paste is cheap and easy to make , as for PPE i wear a axminster APF10 Evalution powered resporator
good luck ,and hope this helps Tim