Kevin Ganzevoort agreed...Canada is possibly the same as the UK so apply for a retirement visa OA while in Canada using your Canadian income as proof of monthly income. You need Health Insurance for up to 12 months (not needed once on an O visa extension based on marriage). Tropical disease report from your Canadian doctor and Criminal Record Report (both to be within 6 months of validity)

Enter Thailand to receive permission to stay up to the expiry date of your Health Insurance/12 months.

You can obtain TM16, confirming your address, from local Thai immigration then open a bank account.

Visit Canadian Embassy in Bangkok to apply for Affirmation for marriage.

Get approved and certified translations of all your Canadian paperwork. (Two days stay in Bangkok)

Get married at local Amphur.

Two months before your OA permission to remain expires apply for extension to remain for further 12 months based on marriage at your local immigration showing your Thai bank account credit and/or monthly international income transfers from Canada, map of your home, individual photos of you with your wife in and outside your home. The outside photo should also show house number/name in your photo.

Be prepared for immigration visit to your home and immigration talking to neighbours about you.

Going with an OA visa first also means you can take your time making sure you really want to marry instead of rushing it and regretting it if things go pear shaped with the marriage

It is supposed to be free.

Years ago, as a rookie I went to my local immigration to get my first residency certificate (I have a Yellow House Book now).

I was asked for ฿100 and stupidly just put a ฿500 note on the desk in front of me.

Like a python strike the note disappeared into his desk drawer with no chance of pointing out I should get ฿400 change 😡

I learned my lesson. After that I verbally stated what I was tendering.