If it is for troubleshooting and maintenance, I use an 8FP4 crt in place of the set's CRT. The tube connections are the same and it will work with your chassis. Plugs straight into your set's CRT socket and just slip it through the yoke. It is electrostatic focus with an aluminized screen so it does not need the focus coil or ion trap. I geberally remove physically the focus coil while using this tube on my RCA chassis.
Here is one currently on ebay.
https://www.ebay.com/itm/12678432782...Bk9SR8aW5suhZQ