Trim is decorative not for "protecting against water and drafts", someone else here will probably have a suggestion for one I am at a loss and why is it set so far back from the siding or is it just an optical illusion?

It can be pulled out a little more, I have set in with 2 screws, still need to wrap the sill. Here's a closer look. My problem is there's not enough room for trim without cutting the siding.

That is a funky edge for certain.

Not sure how you would best trim that out without cutting back the siding.

I will wait for some of the guys that deal more regularly with that stuff.

The picture perplexes me even more as the window should be set proud of the sheathing not behind it. There really is no correct to trim that.

Ok, I'll pull it forward tonight and try to get the proper placement. It's a replacement window, it has four holes in the frame for attachment. I'll pull it forward as much as possible. I have aluminum windows with storm windows. There's no existing trim, the siding butts up against the window frame. This is the first time these windows have been replaced, the house as built in 1959. Say I move it forward so it's set proud of the sheathing, is there a way to trim it without cutting the siding?

If it is a true replacement window it is designed to fit inside and existing window frame which I do not see here. I am getting more confused by each or your posts? If this is installed behind your sheathing as it appears what sort of weatherproofing is in your opening? Where is your drip-cap or head flashing at the top of the window? There may not be trim but the window should have sat on the sheathing and the frame would be proud of the opening. What is this window exactly?

If it is a true replacement window it is designed to fit inside and existing window frame which I do not see here. I am getting more confused by each or your posts? If this is installed behind your sheathing as it appears what sort of weatherproofing is in your opening? Where is your drip-cap or head flashing at the top of the window? There may not be trim but the window should have sat on the sheathing and the frame would be proud of the opening. What is this window exactly?

No way to add wood or composite trim boards without cutting, however if you have a brake and the expertise to use it (or hire someone that does), you can just tack some 1x2 onto the siding, and then wrap them. At the metal to siding interface, the metal will need to be scribed/notched to fit over the siding.
The head will be the tricky part, as it would be far better if you can retro fit a drip cap/ z flashing above the window (under that next siding board). The other option would be to butt the trim up to siding and caulk it, however that is technically incorrect as any moisture that gets behind the siding can run into the opening, plus the only seal on the exterior is the caulk.

Posting some pictures of the original windows may help.Typically around here asbestos siding has a metal J that butts up to casing. I think the best solution would be to cut the siding back and install casing and drip . Great care should be taken when cutting asbestos and may be considered regulated work depending on which state you are in.

+1 to the above feedback.

A talented technician could do something for you.

While asbestos siding is far less injurious than the TSIs and other stuff, be careful with it and read up on PPE.

Its probably not regulated if the homeowner is the one doing the work but that doesn't mean you want to expose yourself or anyone around/near you because of carelessness.

In Minneapolis removal of non-friable siding is regulated by the city. If you are cutting the siding you are turning a non-friable material into a friable one and there is a lot more risk involved, at this point it may be regulated by the State and require an abatement contractor.You could be putting yourself, family, and neighbors at risk and exposing yourself to other liabilities if done incorrectly.

Gently pull the nails from siding around window and cut the siding using a wet tile saw. Keep the siding wet when cutting. It is dangerous when friable or able to create dust. I have this on my house and at the refinery I retired from, we used licensed contractors for asbestos insulation. Just keep it wet, even when drilling, no dust........I've done this at my house and fixing to have to replace my old wooden windows. It is not rocket science, use you head, you can safely handle it without creating dust. Never handle asbestos insulation, it creates dust by just the wind...

I have the same question. Aesbestos siding and metal windows abut the siding. I suppose one could use a battery circular saw and hose...or just throughly wet the siding prior to cutting to create enough room for trim.

a siding contractor would know this.