Before buying any make or model of van you first of all need to identify what you need it for and what is required of it.
With regard to the Ford Custom, the interior cargo area is 1/2cm smaller than the current swb Transit van - 6cm as apposed to 6.5cm. Other competitor vans are around 7.5cm.
Payload is the most important. They have various payload variants-
250 - 700 kgs
270 - 895 kgs
290 - 1100 kgs
310 - 1300 kgs
330 - 1500 kgs.
In my opinion the smallest you could just get as a two man team with 650 liters is a 290 but you would be better off with a 310. (The diesel tank holds 80 litres which is 80 kgs full - another person weight wise.)
As the payload capabilities increase so does the price. You could easily start to let the price dictate which model to buy, which would be the wrong approach.