from my suggestion will be using T5,

t5 can be join together like the photo below

unlike t8 have to cross over

btw, t5 do have fluorescent for cheaper selection

if t8, the shadow gap is noticeable

while t5 giving better effect

YEA, once one dot gone, whole strip got to change

there is an idea height which is 75mm for L box, 75mm for the gap, 150mm height in total, some people do have 100mm gap when the ceiling is more than 3000ht or 50mm for led light ONLY(t5 will be more brighten than led the light if having small gap)