The biggest trick is to keep the barrel from turning in the vise. I bought a Viper. It is a good design and really allows you to tighten down the nuts. The problem with most barrel vises is that their contour cannot possibly fit every barrel. This results in only a small area or ring where the vise has purchase. I try to increase the amount of contact by wrapping some tape around the barrel and then adding another wrap or two to compensate for the amount of taper. The tape helps protect the barrel in the vise. I next wrap some 400 grit sandpaper around the tape (rough side facing tape) to help keep the barrel from turning. Finally, I place some thin pieces of cardboard to help cushion the tape and sandpaper from the steel vise. Then I slowly tighten the nuts like you would when putting on a tire. When think you have it tight, slide a cheater bar (conduit, steel pipe, etc.) over the wrench handle and really begin to torque down on it. Continue until each bolt/nut creaks and groans - then it is finally tight. Insert the action wrench and then use a large hammer (dead blow) and 'shock' it loose. You can heat the receiver, but that may mar the finish.
Tikka receivers do have flats on the side, so a regular wrench can work. Just be sure to use the flats closest to the barrel. There are tremendous pressures exerted in removing a barrel. If you clamp on to the rear of the receiver and hit it with a deadblow, it is possible to twist the action slightly creating a nice door stop..