Bintel have some big discounts on the zwo120mm and others atm. As for the guide scope best to keep the weight down. I have just received a 50mm compact finder guider (Chinese unbranded) good build quality, lock screws in all the right places, only con so far is the dovetail bar could be a tad wider.
http://www.ebay.com.au/itm/191895211366 I have coupled it with a zwo120mc and first trials have been good. (The 50mm guider was supposed to come from o/s but it came in a week from a Sydney warehouse)