if you're flying to an airport where you don't normally fly, it would be prudent to make sure that your handler at dest has a towbar which will fit your particular a/c type.
If you have a weird a/c type then ditto.
1. while you may be able to park at a power-in , power out position... some bigger airports don't have this 'planned' so you end up using two remote bays.
2. Some aircraft are different from others. Airbus A310 come to mind.. some have small spindles and some have fat ones, depending on original customer.
3. Russians usually carry one on board. I've seen an AN124 take 40 mins to push out...first the aircraft is pushed out onto the taxiway using the double headed towbar. It is then disconnected and pulled aside (still near the aircraft). The aircraft does the whole nose opening, ramp-lowering, kneeling thing... which takes all of 15 minutes.. the towbar is wheeled aboard the Antonov by the Russkies (a bunch of them are always onboard) and the kneeling, ramp and nose events are reversed. Parking these things sideways on a normal parking spot is not possible due to wingspan.
Anil