proper way to run conduit on top of siding
Reading your question and comments I am assuming you are trying to install a service drop to a meter. In that case you would want it to be as short as possible and use GRC. I am not sure if you can read the image or not but if you use 2" GRC you can use that as an unsupported riser for the drop any other conduit you may wind up installing a support bracket. That's what I am trying to show you in the image below. 

Remember I said it should be as short as possible. Generally what we try and do is get down to the meter and in this case install a 200A enclosed breaker. Then from there you can run to a main lug only panel and from there you can use any allowable conduit EMT, PVC, etc. Because it is exposed to sunlight over 10' on the exterior you need to factor in derating per NEC Article 310.15 (B)(3)(c). Also Article 310.15 (B)(3)(a) exception will allow you to use Type XHHW-2 insulation on you conductors and you do not have to derate.

Finally in your comment you mentioned an AEP engineer disallowed a run over the garage. Are you sure you have to move the meter? In the state I am in we are allowed to raise the service drop to meet overhead clearances.

These images are from the Oncor book which is our utility company in this state. I don't know which utility you are using or where you are but I am pretty sure they have something similar to this. If it were me I would make sure that the engineer would just allow you to readjust the drop to meet the modern clearances before I would start the project you are proposing.