Professor reviews proposal as a favor, should I send a reminder I am applying for PhD, and in the application I am required to write a research proposal. 

I asked my thesis supervisor to write a recommendation for me, and he agreed,but he told me that I need to work more on my writing and carefully write my research proposal. He told me to have people read for me before submitting it and suggested that I send it to him so he can review it for me as a favor.

I got his email with feedback on the proposal. In the email he wrote "Here is my first feedback." We discussed the review he made and I made changes and he asked me to send him the new proposal. After I sent the email, he told me that he will read it and give me another feedback that same night. That was about five days ago and now he is on a vacation. 

Would it be appropriate to remind him ? I need his feedback because I am trying to submit the application. Should I just submit the application and just assume that he is too busy for me ? I don't want to be naggy and annoying. After all, he is doing me a favor.
Send an email suggesting you don't assume he will offer any more help, but leaving the door open in case he offers some:


  Thanks so much for your help with my proposal. I believe your suggestions have really improved it. Attached is my current version; I will submit it tomorrow evening. Let me know if you have any last-minute suggestions before then.