the funny part about loading stuff is how fast the weight can go on. To securely carry 20lbs on the front through all kinds of stuff where front panniers won't smash on curbs and rocks it helps to bring the panniers up a bit higher, and as long as you're doing that have a platform for keeping items off the front wheel. So for 20lbs of stuff there's about 5lbs of rack and bags. Going with the mini rack and compression sack/handlebar bag you can carry 10-lbs between the bags and top of the fork with about a lb of support structure.