I'm from South Africa, did find a lovely girl, planning to marry. What visa is the best to enter Thailand, single or multiple. TR visa the best to enter, 30 days to 60 days, can extend to 30 days.

Depends on when you plan to marry. A double entry would be best. It would give you 60 days on entry which can be extended for another 30 days at immigration for 1900 baht. You then do a border crossing and when you come back in you will get another 60 + 30. It would give you almost 180 days to get all of your ducks in a row to get married and season the required 400k baht to get a 1 year marriage extension if that is the way you plan to go.

You can marry on a TV, but it would either have to be converted to a Non-O or you you go to a neighbouring country to obtain a Non-O. Only a Non-O can be extended for marriage purposes.

Only a Non-O can be extended for marriage purposes.

Actually it not so. A 60 days extension for visiting a Thai spouse or children can be given for any type of visa, or visa exempt. And, for a tourist visa it can can be done (at least in some offices) after a 30 day extension. This type of extension extension does not require any financial proof.

Many thanks, can you tell me more about the Non-O visa

It is a non immigrant O visa based upon marriage to a Thai. You can get a single or multiple entry visa. Each entry allows a 90 stay. You can apply for one at most nearby embassies and consulates.

Once you get married you would need your marriage certificate and copies of your wife's house book registry and ID card.

So I just need to convert to a Non-O, and rather do a visiting Thai spouse, and not a marriage visa

Their is no visa called a visiting Thai spouse or marriage. There is only non-o visas based upon marriage.

You can apply for a 60 day extension of stay at immigration to visit your wife with any type of entry.

You can apply for a one year extension of stay based upon marriage after you have a non-o visa entry, You must show 400k baht in a Thai bank in your name only for 2 months or proof of 40k baht.

So I can go to Thailand on a Tourist visa, convert it to a Non-O, after I am married, and extended it as a visiting Thai spouse am I correct in my thinking

You can only do the conversion at Bangkok immigration and it takes two trips 15 days apart to get the visa/entry stamps. You must meet the financial requirements needed to apply for an extension that I mentioned to apply for it. The money does not have to be in bank for 2 months is the only difference.

If you are not living in or near Bangkok it would best to go to a nearby embassy or consulate to apply for a non-o visa.

I understand the non-o visa