I did do a slight angle(~15 degrees) on the second drag I made out of some 3" schedule 40 steel pipe I had on the property. It was about 6' wide shaped like a U so the back posts act as a counter weight and if it gets to heavy they tilt up and dump some of the load then resume. The only thing I hate about that drag is that the it is very heavy I plan on fabricating one possibly out of aluminum to help with placement and a angle change option. Made of a pivot point and lever/pinned linkage system. My only hesitation is I am not sure if it will take the abuse like steel will.

The pins which are just steel rebar pins secured with a bent 16d nail tend to snap off before the strap even starts to groan, plus working offshore I collect "out of date" straps. I have yet to part one as a 2" 2 ply which is rated for ~4200 choked(as actual rating depends on the manufacturer). If I do break one which hasn't happened yet it would more than likely be when I am pulling stumps(When in doubt I always go bigger on my rigging 4" 4-ply is a hard strap to break without tearing off your hitch). When she drives she gets anxious as the truck is lifted and she isn't comfortable with my tractor(to many levers) so she doesn't really maximize the pulling power plus as previously stated the pins I am using tend to just snap off. I do however appreciate the concern for everyone's safety involved though.

Also the angle on the second drag does seem to make it more effective that and the fact that it weighs in at about 50-60lbs more. The rebar pins/stakes I am using are convenient as they have pre-drilled holes ~2" on center and a 16d nail fits tightly in them. This allows me to change the depth rapidly if need be.

Got to cut it short dinner plans sorry.