well, it is quite hard to say how much he can and should drag. that depends on how long you are planning on letting him drag weights, on what ground (snow, sand, etc) he will be draging weights, if the landscape is flat or if there is a lot up and downhill on the way, etc.
if we take my male as an example.
he weights 70,5 lbs (little body fat) and has b hips (ofa fair i think it is) on both sides. he is 4 years old in january and has been training all his life. right now we have snow and temperatures are no colder than 14F (under that temperature we do not train). he has 88 lbs chains behind him and drags 0,6 miles, the landscape is quite flat. he could easily drag 22 lbs more, but we don't have that many chains. if we go longer, he gets to drag about 55 lbs, but then he has to drag up and downhill a lot.
now, when you think about what the surroundings are there where you live and what temperatures you have. then, you have to think about how much body fat there is on your dog. because he cannot work with fat and it is dead weight that he has to carry (with dysplastic hips!). then you have to think about how much he is trained, both strength and endurance. in the beginning he should drag a weight that is so light that one doesn't notice that he is draging and after his work out he should show no signs of pain. it is actually quite hard to tell from a distance, not knowing the dog and not seeing it when he works. but i wouldn't let him drag more than 33 lbs at most for quite a while and i would increase the weight up to 33 lbs slowly and the distance slowly aswell to about 1,8 miles at most to start with. if he starts limping after work out i would cut back on both weight and distance again and i wouldn't start training again untill he has stoped limping.
the most important thing is that you keep him as slim as possible. in summertime i would let him sim as much as possible. simming is imo the most gentle form of training and the best way to gently build up muscles.
somtimes, proffessional pet massagers will come to pet stores. you can book a meeting with one and he/she will show you how to properly strech and massage your dog and what to think about regardning his hips. you can also see if you local dog club offers couses or ask you vet if he/she knows of any. a dog trainer at your dog club will be able to help you further with proper training. then, there are quite a lot of good videos about dog massage and streching on youtube aswell. if i find a nice example, i will post it later. i don't have quite time for lokking for one right now.