Help with I-470 form Application to Preserve GC

I am a Green Card holder and completed the residency requirement for applying Citizenship. I will be eligible to apply citizenship next year. Now I got an offer to work in India from my current US based company. I want to take this offer, but preserve my residency while I am away and apply for I-470.

I read the requirements for applying I-470. It states that I have to be in US for a continuous period of one year after getting my Green card. I went to Canada for a week on vacation in the very first year I got my green card. Please help me understand whether I can apply for I-470 or not. Also please let me know the processing times for I-470 and if I can leave the country before it gets approved. Thanks