Even if you apply for FLR again you still need the same evidence.
"We need 6 letters or other documents addressed to you jointly or in both your names. If you do not have enough items in your joint names, you may also provide items addressed to each of you individually if they show the same address for both of you. The dates of the letters or documents should spread over the whole 2 years. They should be from at least 3 different sources."
The only reasons for applying for FLR instead of ILR are:
1) you delayed your journey by more than 3 months (doesn't apply for people who came to the UK on a fiancee visa)
2) you haven't pass the Life in the UK test
3) there are issues with your relationship with your partner
Your best bet is to try and find as much as evidence as you can, and make sure that you've got good evidence for the next couple of months to use when you do apply.