It's a very personal thing. I did D/L and it was best for me. Had enrolled for residential but changed my mind. It was great. I could play golf when it was nice, and make up for it later. If I couldn't be bothered one day I wouldn't do anything. Similarly on days when Mrs SK was working late or I was in the middle of something I liked, I could plough on till late. As FFF says you work at your own pace. And the refresher course really does get you match fit.
You obviously aren't thick so won't really struggle with the material. Indeed if you grafted you could have it done quicker than residential. I did it in the same time, around 6 months. And I would say I spent on average 3 hours a day at it. It ain't difficult, just tons of it.