Does your flange rest on top of the finished floor as it should or is is recessed? If it is on top of the floor, then a standard wax ring with no plastic funnel is all you need. If the flange is recessed, then a thick wax ring would be in order. If the flange is considerably recessed, then spacer rings could be used. We really need more data on your situation to be more specific. As far as flange bolts are concerned, it is not difficult to shorten long bolts. A lot of us find using an extra nut to secure the bolts to the flange in an upright position to be helpful. Set the toilet on the flange without a wax ring to determine where to cut the bolts. A file to sooth the cut end helps get the nuts started. I'd suggest trimming the bolts to length before installing the toilet. It's a bit tricky sawing them when in position. The length does not have to absolutely perfect, there is room for a tad more length than actually necessary. And, if you screw up, the toilet isn't damaged and new bolts are cheap.
Hardware store items for toilets
Notice that the bag of bolts includes four nuts and four washers.