i dont know the weights of all that gear. i only clean trad.
but if it was me (and one day will be) i'd get the bigger one - but take into consideration, can you park it near to your hosue without upsetting your neighbours, can you drive something that big, can you afford the bigger one. also check the insurance on the two (over the phone is best) and then decide if the bigger one is best, after all - you'll look to expand your business one day and then you will want bigger tanks, more weight - so you'd be best of getting what you can first off.
you could always buy the short wheel base van, with the payload upgrade to 825kg. so you have the lower insurance (i guess) the smaller van, easier to drive and park - better for oyur neighbours, but still all the weight oyu need and more to expand.