Should I wait to complete my Non O A visa application until closer to my arrival in Thailand in April?

You should complete your applications at a later date. Check the processing time for the embassy that you will apply in (should be on their web page) and add a week or two to the estimated time.

I ran into this a bit and if I recall you have to submit the insurance papers with the visa application so there is going to be a lack of sync regardless. But it’s still a better deal if you want to keep your money in your home country bank.

On my last half of my OA second year and so far it has been a better investment than the non O because I gain interest on my money sitting in my bank at home where Thailand really doesn’t pay interest.

It’s more important to get your application in order and correct because if you get it wrong you have to pay again.

Have you considered the non O visa instead?

It does not have the same insurance requirement (you can still get your own insurance).

The non O can be extended annually in Thailand, but you would need to deposit 800,000 baht in a Thai account.

The non-OA is a 12 month visa and it starts from the day it is issued by the embassy. Getting it this early would be wasting many months of the visa.