Hello everyone! 
I'm a new member here, but I have been lurking around on this forum and some others for the past few months trying to gather as much info as possible for my first FLR M application.
Let me give you guys a little background to start... I am currently on a Tier 5 Youth Mobility Scheme Visa which will expire in January of next year. My now husband and myself have been dating since 2012 and very recently got married on September 21st, 2018.
We are both non-salaried and plan to combine our income using Category A. We have a premium service centre appointment booked for November 13th at the office in Croydon.
Now on to the questions!
#1. How many payslips should I include in my application?
The guidance says to provide 6 months worth, does this mean only 6 payslips or however many you need to cover the 6 month period they require? I've come to realise that even if I submit 7 payslips, they will be 1 day short of covering a full 6 months
and if I submit an 8th I'll be nearly a month over.
Since I'm non-salaried this makes figuring out my gross annual income a bit of a headache.
#2. My husband is paid every 4 weeks so, as per my above question, how many payslips should we include for him? He was paid twice in June as well, I'm unsure if this is going to affect the way we calculate his income.
#3. What relationship evidence should we supply in support of our application?
We have been living together in the UK since I arrived on my YMS visa in January 2017. We were planning to submit correspondence (utility bills, credit card statements, NHS letters, HMRC letters etc.) that covers the period we have been living together before and after marriage as well as our marriage certificate.
Is this sufficient or will the ECO be expecting chat logs (many of which have been deleted due to changing phone numbers/providers, MSN being swallowed alive by Skype etc.) and photos of us throughout the duration of our relationship?
Thank you so much in advance and If anyone can help us out we would be thrilled! Thanks a million. 
IN your circumstances seems like evidence of cohabitation you have in mind is good enough, you may throw in a couple of wedding photos showing friends and family and photos of the two of you in social context.
As to payslips again please understand this is not about how many there are, it is about covering 6 months IN FULL, so my novemebr 13 you make sure your most recent pay slip and bank statement are no older than 28 days, and then subtract 6 months from the date of most recent one. Has to be full 6 months of evidence, and each payslip supported by bank statement with corresponding credit.
If you are relying on cat 1 as nonsalaried, in each case when each of your 6 months payslips are averaged, and then the average is muptiples by 12, and they are added together, must be above the requirement.
Also it's a bit tricky for a T5 to rely on his or her salary for a self-sponsored spouse application, since conceptually you cant possibly be filling the permanent post. make sure your required employer letter refers to the end of your contract according to your visa. i explored this previously and found that -- why not, but again be aware this is not very usual.
****Disclaimer: I am a Level 3 OISC advisor and so my opinions are informed by knowledge of the law and years of practice. Yet, no opinion given without detailed review of an individual case should be taken or treated as competent legal advice.