a reptile bulb will not hurt your plants , there just isnt enough uv produced by them at a high enough watt per bulb (i use many in my rooms) , although there is enough to help boost resin production
i use them the full 12/12 in my photo room and full 18-24 hrs in my auto room
MH in the last couple weeks will indeed help a small amount , they do produce a small amount of uv lighting , but be careful not to switch too soon as you will get leafy buds and think you did well in the yield department when in fact the hps would have given you more actual bud swelling instead of leaf growth (remember , there is a final BOOM in bud swelling the last 2-3 weeks)
peace