Incremental training and unk symbols ssiue

I have been trying to setup a Hindi-English NMT model with a deep multi-layer (wmt16_gnmt_4_layer.json) RNN which is unidirectional and uses LSTM as a recurrent unit.
And the translations from Hindi to English are pretty ok with “num_train_steps”: 340000 and now I want to improve the quality of the translation to a certain good level with the help of adding new corpus from another source.

I want to make sure, the steps that I will follow to start the incremental training is correct -
-Generating preprocessing data (not the vocab) using the wmt shell script from nmt repo.
-Vocabulary to be used from the previous preprocessed data.
-copying the checkpoint, translate.ckpt-340000.data-00000-of-00001, translate.ckpt-340000.index, translate.ckpt-340000.meta to the new out_dir
-Using the dev/test set from the previous preprocessed data
-Modifying the “num_train_steps” as 350000 in json file.(wmt16_gnmt_4_layer.json)

-Starting the training using below command –
sudo python -m nmt.nmt
–src=hi
–tgt=en
–override_loaded_hparams=true
–hparams_path=/home/atladmin/nmt/nmt/standard_hparams/wmt16_gnmt_4_layer.json
–out_dir=/home/atladmin/nmt_ckpt
–vocab_prefix=/home/atladmin/nmt_new/vocab.bpe.32000
–train_prefix=/home/atladmin/nmt_new/train.tok.clean.bpe.32000
–dev_prefix=/home/atladmin/nmt_new/dev.tok.bpe.32000
–test_prefix=/home/atladmin/nmt_new/test.tok.bpe.32000 \ > nmt_hindi_log.txt &

Please do let me know if the above mentioned steps can be used for incremental training for the new corpus.

Also when I tried the above steps and tried to do the translations there were many unk symbols coming during the inference.

Sorry, this is not the right place to ask about the TensorFlow official NMT tutorial. Try opening an issue on their GitHub page.