this link shows a picture of a roller striker.
http://www.aplant.com/catalogue.aspx?id1=110010 if you've not googled it.
this the mag' bull float.
http://www.speedcrete.co.uk/magensium-bullfloat-complete-i102.html
this the trowel although they call it a float its more of a trowel it leaves much finer fat lines compared to the float and a finer finish
you could just use this but you'll get a better finish faster if you use the mag' first.
and if can hire these
http://www.speedcrete.co.uk/lightweight-texas-placers-i55.html they make levelling out concrete much easier
than a rake.
I've never seen a beam screeder in use so I don't know how hard they are to get a level finish.
the roller striker takes two to pull, you are out side your shutters on which it runs, it can be hard to pull if you've not levelled your
concrete very well but if you pull up half a meter in front of it you can ride it over it then pull the heap down from the front,
if you've got a hollow you just pull a heap back the other way. it normally takes three passes to get it level, as soon as you stop pulling
any stone that's it any more passes will leave your concrete hollow in the middle.
if you haven't got a spec sheet,
as for a concrete mix if it was for myself then I'd ask about a pad mix this type of mix has a additive to reduce bubble size giving you
a stronger slab and the mix is more fatty and less water comes to the top so you can get a better finish,
order a 60 slump and if its a bit stiff the driver will add a little water.
http://www.aplant.com/catalogue.aspx?id1=110002 the trowel.