I wouldn't worry about 90 degree bends either, you can always put a chamfer on the corner to correct the capacitance but it's unlikely I will do any PCB design at 10s of GHz. It's funny, a long time back I read a report from some "EMC consulant" who was advising somebody beacause a logic PCB with a not very fast microprocessor was failing emissions at a few hundred MHz, he said you had to chamfer the 90 degree bends to fix the problem. It was odd because there were no 90 degree bends and he had failed to notice the rather long slots in the grounplane. I think he got paid something like £500/day for that. Also seem somebody go to a great deal of trouble to route an RS485 pair as an HF 120 ohm balanced pair, some people just havn't got a clue. I once routed a Gige ethernet flexi cable with lots of serpentine wiggles and I think I got the mismatch down to 20ps, a complete and utter waste of time but I was bored and it was fun. I suppose curly tracks have their place and they could have been used to get more clearance.