Canadian in China, moving to California

Here's my situation. I am a Canadian citizen, born in Canada (but currently a non-resident), working in China for the last few years for a WOFE (Wholly Owned Foreign Entity) company owned by myself and 2 US partners. I need to move to California to continue the business and I'm unsure what kind of visa to apply for.

My first thought was a L1 visa. There is a US company which is also owned by my 2 US partners which could 'transfer' me over to the US, but even though the US and China companies are operationlly linked, there is no formal branch/affiliate relationship.

I have an MBA, BSc Eng. and about 20 years of mgmt consulting and senior management experience so I'm sure I could qualify for the L-1A visa. However, proving the affliation of the companies is the difficult part.

My second thought was a TN visa. Not as flexible, but much easier to get, right? The company in the US could hire me as a mgmt consultant and my degrees & experience should be sufficient. However, here are my concerns with this:
a) should I have the company submit an I-129 first, or just apply at the border?
b) Should I enter the US coming from China or from Canada? does it matter?
c) does my being a non-resident of Canada matter? I don't own property in Canada which I understand is important to show that I don't intend on immigrating to the US. However, my wife does own property in Shanghai.is this helpful?

And just to be clear, I'm not planning on living in the US fulltime.probably only 2-3 years max. And I have no desire to get my green card.

Can anyone give me some advice or direction?

TN-1 and L-1A for Canadians aren't visas, you apply at a class A port of entry. It might be a better idea to apply at a Canadian POE because they will be more familiar with the process.

Management Consultant is the most heavily scrutinised NAFTA category, so make sure you have all your ducks in a row before trying that one. The fact that you're coming from China not Canada puts another wrinkle in that one.

I'd say go for L-1A if you can manage it, if only because they have a longer term of validity. Plus if you change your mind and decide you want to stay, it's dual intent and getting permanent residency is easier than TN-1.