Walk the oil rings on. Use an expander on top two.
The tool is like $10.  Why not?

Walking the top two rings on can easily result in the ends of the rings getting bent.

I walked'm on because I din'unt have a ring put'r on'er tool butt......ring install tool is the best way.
6s6

You haven’t made any?😁

Every set of ring instructions I've read will tell you to use the tool.  You have to walk on the oil rings, but they are flexible.  The 2nd and compression rings are not.  Trying to walk them on is a good way to break them.  Counterintuitively the higher performance the ring set is the more likely it is they will break trying to walk them on.

Speaking of rings, since this will be the next question, buy a tapered ring compressor.  The ratcheting universal, one size fits all compressors are junk that will also cause you to break a ring.  The worst part is you won't know the ring is broken.  Using a tapered ring compressor you can literally push the pistons into the bores with two fingers.  I bought a Summit 4.030" tapered compressor over 15 years ago and have used it on three engine builds, and on both Fords and Chevys.  The idea that it only fits one size is a weakness is therefore not really all that well founded.  Also, they aren't expensive compared to the damage they save you. 

UPDATE

I walked the oil rings on and purchased the tool for the compression rings however I found I had better control expending them by hand rather than using the tool so thats what I did on most of them.  (probably operator error on the tool issue)

The ring compressor I purchased from amazon worked well AFTER I had it adjusted properly which took a couple of piston installs before I had it dialed in properly.  I can see where the specific over bore sized ones would work better if you were doing the same size all the time.