I have both the DD hammocks, Travel and the Frontline, I am 6' with a chest measurement of 50", and have come down to 17 1/2 stone from about 19 over the last year, and have had no trouble with the DD's,
One thing I will advise is that you DO think about the whoopie slings, I have just got some and not only are they quick and easy to adjust, the Black webbing that comes with the hammock seems to always stretch with my weight, so I dived in and brought a set, Now i set my hammock at the height i want it and its there in the morning, I used to have to set the hammock high to allow for stretch or I would be on the floor a few hrs later.
And as for customer service I cant fault DD at all, for example I purchased the whoppie sling set, it arrived the next day, that weekend they were being used, i did have an issue with damage to the Tree Huggers in the set after hanging for two nights, they also damaged the tree... I normally use my home made HUggers but for the cost of the set thought i would just buy a set as they were in the kit and I also needed two Krabs as well, I emailed Nick at DD with Images, within 8 working hours had an email back saying that they have not had the trouble reported with the new type Huggers they are now selling, and they would send a replacement set, and gave me a choice of a newer style or older style the next day..... cant beat that for service.
I am a very happy DD customer.
The only over Advice I can give you is go to a meet, try a few hammocks, for size