Switching lights

Made the switch. It probably to early to tell but after few days the plant sure looks happier. It has very nice color and it looks to me like the light is getting down in the plant to the stuff that is below the main canopy better than before.

It would not be a bad if it has the same lighting area foot print. eg 4x6 vs 2x3 t4 tubes come in an array of sizes so if the plant is getting the same light exposure all over the canopy I don't see why not. Look for hot spots on the PAR/PPFD map the light may come with. Most manufactures are not including one of them. Good Luck!

Certainy switch to LEDs, but why not use them both for the flowering phase, it won't hurt them.

No, you will not damage your plants, if anything you'll be helping them avoid heat stress and so on, smart move to led, it's the 21 century think them old lights should be done away with they add like 40% costs to your grow. Good luck

Yes, better light, better bud.