As you probably know, most people tend to go by 1 or 2 main things when determining "flower readiness"

1: Alternating nodes...a sign of sexual maturity (you dirty little plants!)

2: Height...Many strains will double or triple in size once put into flower so once they're a certain height...in they go.

as far as the fimming goes...you may want to wait to see that they have recovered from the FIM and the new growth is substantial. Usually 2 or 3 weeks for me but i veg longer than most, depends when you FIM em i guess. you say a week and a half? if the FIM'd top is still real small and showing fresh little half leaves (looks like they've been chewed or cut) i'd let them go another week or so until they are a little bigger and spread out a little more. they'll probably do fine either way.

so yeah, put em in and watch the magic.

keep us posted
Skeet