How close can CFL bulbs be to one another?

I have a power bar/power strip with 7 outlets, I can fit 4x23 watt bulbs on one power bar, but the bulbs are very very close to one another, sometimes they touch.

Will this be ok?

If this is not ok, then I might have to go with 3 bulbs per power bar, but use 42 watt cfl bulbs instead of 23 watt bulbs.

Try not to let them touch, I have had them w/in CENTIMETERS of each other!
Just so ya know I know:
https://www.rollitup.org/cfl-growing/146691-new-cfl-grow.html

3 42 watters are probly better than 4 cheapos

you can have them safely 1 inch away from eachother, with a fan blowing on them, even closer.