Hire a structural engineer.

thats plan #2. install ridge beam and tie rafters into that. i could sister bigger material to 2x6 rafters. use 2x8 or 2x10. or leave rafters in place and sister on a scissor truss to each rafter. there are 10 rafters so its not a huge job. so there may be 3 different ways to rebuild interior support structure while leaving exterior roof/shingles in place.

If you are in MN, there are two possible solutions. Install a very large ridge beam supported at its ends with posts to the foundation and sister 2x8's to the existing rafters or remove the entire roof and replace it with scissor trusses that have a much greater roof slope in order to achieve a 4 in 12 slope for the ceiling.

Both options would require the use of a structural engineer and because of the large span and the large snow load both options would be very expensive.

Unless you want to build a framed roof that meets code completely ignoring the trusses (big $$) you need a structural engineer to modify the trusses.

Most likely only the truss manufacturer has the data needed to modify them.

Different grades of wood are often used in different portions of a truss based on the load that member will be carrying.

A low stress member may be low grade wood to save money, while higher stress members have a grade suitable for their loading.

Since the manufacturer is responsible for the whole design, their is no requirement for grading stamps to be left showing as with a framed roof.

I have 4/12 rafters now. I want a 2/4 roof trusse when done. Ext pitch stays the same. Inside will have vaulted ceiling. With plywood sheathing and t&g boards, flush ceiling lights, many more exterior windows to take advantage of large sloping lot. Awesome.

The problem with a site-built low-sloped scissor truss in snow country is that its vertical deflection will probably be large enough to allow the tops of the exterior walls to spread outwardly (horizontal deflection) more than is acceptable but only an engineer who has seen the project can tell you for sure.

Your insurance company might decline paying out a claim for any home modifications unless an actual professional was involved and signed off on the project. Proceed at your own financial risk only if you can stand the hit of losing everything. Of course, Darwin might prevail and you might not survive to file a claim.

{{!gwi}}

And, of course, one of the most famous snow load related roof collapses.
{{!gwi}}

The simple solution is usually the best. I recently removed the rafters ties and added four 14" LVL's at the ridge of a house in Cambridge, MA and was able to put the ceiling under the existing reinforced rafters.

I see the 6 studs holding up ridge beam. Lots of wood. Do they sell 2/4 scissor trusses in MN? I assume they are built with 2x6 matl?

The post is a 6x6 PSL as specified by the engineer.

You should stop thinking of a scissor roof truss like a commodity or that it can be easily designed or safely site built. You are in way over your head. Stop ignoring good professional advice and hire an engineer.

Baloney. U know nothing about my abilities. My brother managed the company that built the omni-saw trusse manufacturing machine. I worked as a cad designer for several years and have been around the building design industry for years. A trusse can certainly be built on site.

Then the next question would be why would you be on here asking advice?

Get real here. If you knew enough to calculate the loads properly here, you wouldn't be on the internet trying to find out the information to hack the job from the ass end. If you can't afford the relatively low cost fee to consult a structural engineer, then you can't afford to do this project. It has way too many potentially dire consequences for your family if done incorrectly. Do you really want to be so obstinately prideful of your ignorance at their funerals? Only proceed with this if you are unmarried and there will be no one else in the structure to suffer the consequences of it's collapse.

"built the omni-saw trusse manufacturing machine"

And that says nothing about his or yours ability to design the trusses the machine will be used to build.

Did you even need a license of any type to design and build the machine?

Truss designers are normally a PE or working under the direct supervision of a PE.
The folks at the factory doing the actual assembly are just laborers.

If all you can claim in the way of professional knowledge and training is something your brother did and having once worked as a CAD drafter and being "around" the building design industry you should be begging the professionals here to help you.

No one has said a scissor truss is impossible to build on site; they're telling you that you don't have the knowledge and experience to do it correctly and that an incorrectly designed scissor truss is a seriously dangerous thing.

I'm out of this discussion.

Hire a structural engineer, or a realtor. All the mumbo jumbo about CAD experience is just blah, blah, blah. If you do it on the cheap, you will pay eventually.
So are you and your brother not on speaking terms?
Buy the best and you'll cry only once.