you can always do the editing after a kor-english translator does his/her translation editing first. that means you will focus only in the english. These guidelines by the academy i believe answer your question
EDITING
BECOME AN APPROVED EDITOR IN THE TEAM
Subbers are not allowed to edit unless the subtitle is incomplete (only subs half of the segment) or completely wrong. Approved editors from the editing team are the ones who takes care of things such as wording, grammar or punctuation issues.
TRANSLATION EDITORS
Some teams have delegated editors to become translation editors. They are editors who are fluent in the video’s original language and English. Specifically checking whether the translations are correct.
PRESERVING THE MEANING OF THE SENTENCE
Translation editors should try to preserve the meaning of the sentence as accurate as possible.
PRESERVE THE TONE OF VOICE
If sarcasm was used, please edit the translation to preserve this.
INCLUDE NOTES OR EXPLANATIONS WHERE NEEDED
Translation editors should check translations of idioms and slangs closely and where necessary provide notes or explanations using the format taught in chapter III.
GENERAL EDITORS
General editors should be fluent in English and be very familiar with the grammar and punctuation conventions used in English.
MAKE MINIMAL CHANGES
To respect the contribution of the subbers, please avoid making any unnecessary changes. For example:
do not edit the subtitle if it is only to add a break to the subtitle unless it is needed in the situation of 2 speakers. (The 2 speakers must be placed on separate lines)
if the original sentence is correct in terms of grammar and punctuation then please do not change the sentence. Only make a change if the original subtitle has an awkward choice of wording.
Do not edit the subtitle if … was not originally used to indicate a pause.
BE AWARE OF THE GUIDELINES FOR SUBBING SO THAT YOU CAN MAKE APPROPRIATE CHANGES OR ADDITIONS
Please be aware of where italics, music symbols, round brackets and square brackets should be used to be able to add these in when editing.
These can be found in Chapter III.
HAVE AN ASSUMPTION THAT THE ORIGINAL SUBTITLE IS TRANSLATED AT ITS BEST AND PRESERVES MOST OF THE MEANING
Please do not try to rearrange a grammatically correct sentence as it may change the meaning of the sentence. This is especially so for Chinese. A small change in the wording of a sentence could change the whole meaning of a subtitle therefore please assume that the original subtitle is correct and make punctuation/grammar changes where needed only.
GRAMMAR AND PUNCTUATION EDITING
General editors are assumed to have knowledge of correct English Grammar and Punctuation. This includes the correct phrasing of a sentence, correct tense and correct positioning of full stops/periods, commas, questions marks and speech marks.
These will need to be included where needed and also follow the guidelines in Chapter III.(you can read this at http://nssacademy.weebly.com/subtitling-guide.html)