I haven't tried pollinating vanilla flowers but I have been successful with other orchids. The normal proceedure with orchids is to remove the pollina at the end of the column which is the part of the flower surrounded by the lip. Usually found on either side of the anther located at the tip of the column. Place the pollina into the space just under the anther. If you look under the anther you will see it. The pollina takes some time to grow into the female part of the flower to fertilize the seeds. From what you say you have had some success. Perhaps your problems are cultural such as not enough fertilizer etc. as orchids will abort seed pods if they cannot support them.

I also have a vanilla orchid plant which is well over 2 meters tall but so far has not flowered. I have had the plant for 2 years and it has grown well. Each season the stork and leaves have grown larger and the aerial roots which first twine around the branches of a shrub then run down the branch. I feed the vanilla with a mixture of water soluble fertilizer (called zest) and fish emulsion every fortnight. Most of my other orchids except vandas flower ok. All of these plants are grown in an open courtyard. If you have any thoughts I would be pleased to hear them.

Regards,

John Driscoll

PS. I have visited Hawaii several times, great place. Mahalo.