Hey guys, I'm new to the forum, so please be gentle!

Ive joined the site as I'm doing my research into resin bound surfacing. My father and I are going to have a go at the surfacing  process, and are pretty hands-on with most building work. We will be hiring a forced action mixer for the job, have 2 tonnes of aggregate (1 tonne of fine 1-3mm dry aggregate, and 1 tonne of slightly larger 2-5mm dry aggregate) on the way (delivery expected early next week).

My main query is with regards to the actual resin itself. Having looked on several websites, and having made a few calls for quotes + information, I am finding that the price of resin varies significantly:

For example a company by the name of Adbruf (http://www.adbrufdirect.co.uk/resin-paving/resin-bound/) are selling resin buckets for £47+VAT, and other places are selling what appears to be the same product, albeit with a different brand name for close to £200 a bucket?? 

What I wanted to know is does the brand make a big difference, and if so, is there anything I should opt towards? Would anyone recommend any product in particular/direct me to the right person? Afterall, I dont want to buy 20 buckets of Adbruf only to find the mixing is inadequate/doesn't allow for fully adhesion! (Assuming 2 tonnes of aggregate, my research suggests 1x 6.75/7.5kg bucket of two-part resin per 100kg aggregate = 20 buckets)

Finally, my last question is with regards to the mixing process itself, several guides/how to videos mention the incorporation of fine sand into the aggregate resin mix - is this necessary and if so - what are the pro's and cons?

Apologies for the long winded message and several questions, but your help will be much appreciated! PM if you can help, or reply in this thread!