I have a White 271 tandem disc and it is not cutting a space just behind the pulling tong it seems like it is just time to replace the cutting disc's with some new ones. So here is the question, I have some plain disc's and I was thinking I would replace the front row disc's with notched disc blades. It seems the notched blades cut a lot easier and cut deeper. The other disc's behind the front row disc would be plane disc's. The other question is I see a lot of these disc's are made in India or in South America, some are 3.5mm all the way to 6mm. I know the thicker 6mm disc will last longer but they are a lot more expensive. Nichols Tillage Tools seems to be real good quality Shoup is another good supplier. Who would you buy from. If I am going to replace the disc I want to do it right. Thanks....Phil