Long residence 20 years

[Meraypass]

Hi

I am looking to apply on the basis of 20 years Long Residency. I have enquired from several solicitors but have received conflicting replies on below two;

Form: Which form do I need to fill in; FLR (FP) or FLR (LR)?

Evidence: How many months for each year do I need to submit the evidence for to HO reasonably? Some say almost every month of the year; others say 3-4 months per year would do.

Can someone please clarify?

Thanks

Regards