Jerry, I looked at those tubes....yikes, 980 lumens from 108 LED's??? Isn't that about 3X the original tube??
What did you mean you used 4 strips in each tube?? One thought about changing the brightness might be to change the rocker switch from on/off to a high/off/low rocker....should be simple to control either one or two tubes plus you can run each fixture at a different setting if so desired.