I don't like hammering t-nuts, too risky if you miss with your hammer swing. Also is easy to get them installed crooked, if you don't tap them in evenly.

I pull mine in. I use a special tool a friend of mine made for me, will try to grab some photos to share later. But, the 'old' way I did mine is inexpensive and easy!

A good piece of hardwood, fairly large size, padded with something so it doesn't marr up the playfield surface
Drill a hole through the hardwood for a fastener with the same thread pitch as the t-nut, use a healthy size washer under the head of the fastener to spread the load across the playfield, so it won't marr up or dig in, and pull it in.

Does this risk putting alot of pressure on the threads of the tnut as its teeth try to sink into the wood?  For those that have done wholesale PF swaps (which I have some to do), what method has worked best for you in this case?