New seat for larger child, sensory considerations

Not sure if this should be in special needs?
My Autism Spectrum 3 year old is having space and sensory issues in most of our seats and with the Ride Safer Travel Vest.
I'm on a very limited budget so it restricts my options considerably.
He is 34 pounds and has been forward facing, as it is increasingly difficult to keep him rear facing with our options and need for three children across often. He is tall in the torso, leaving about 1/2" of harness height above his shoulders in an Evenflo Titan. I think he is now even with the CoscoApt40 when forward facing.
The Titan harness is also too narrow and horribly rubs his neck. I switched his seat with my youngest's Britax Marathon with strap covers. This fixes the height issue but the harness still rubs more than he can tolerate.
Is there a forward facing harnessed seat, under $100, that will accommodate his torso length AND has wider harness at the shoulders?
He gets so worked up about it touching his neck that he begins choking himself
The Ride Safer Travel Vest gets the same reaction from him even though it allows for more neck room, something about it touching him just drives him batty. We have tried to limit its use considerably, but sometimes have no other options for three across. Any experience with this issue?

Have you tried a sure ride? It has high harness slots, 19" I think....Anyway, it might be with a try. I think target and toys r us carry it. It's about $99, and goes on sale fore $79 often.

Maybe someone else can chime in on the neck width of the harness.

I think the even flo seats commonly have the too close harness issue... :-/ you could try a Traci nautilus... I've seen them a few times on no better deal for $94-96...

The Evenflo seats are going to be more budget friendly for you, plus they are more likely to fit 3 across. However, there are LOADS of seats out there w/taller top harness slots than the Evenflo Titan or the Cosco Apt (which is great for rear facing b/c of it's tall shell and height allowance, but is awful forward facing as far as harness height goes). The new Evenflo Sure Ride will give you more harness height than any other seat besides the Britax Frontier line, and with deals and discounts, you can get it between $79-99. If he still fits in the Titan & the Apt, he's not that long torsoed (my kids would have been out of those by age 2, at the most..my nephew, before a year!), so he would have several YEARS in the Sure Ride, quite possibly till he's 6 or even 7.

I know that the harness straps are a bit closer on the Evenflo seats (some of the Cosco/Safety First ones, too) and that not all of them come w/strap covers. You can call Evenflo and ask if you can add thin baby socks over the harness straps (cut the toes off first) to cushion it a bit. They may say no or that they don't recommend it. At that point, it's a parental decision. For my own child, I might consider it in your shoes. I have a soon to be 8 year old with high functioning autism, and many of those sensory issues were awful around that age.

The Harmony Defender 360 at Walmart for $99 is a nice, cushy seat, too. I think it does come w/strap covers..and maybe the shoulder harness slots were a bit wider, too. I can't remember. It would also last him a few years in harness mode.

Whatever you do, make sure you pull his shirts in between the harness and his neck. If he'll let you, maybe you could slip a short sleeve button down shirt on him, over his outfit (leave it unbuttoned), so the collar will cushion between him and the harness. It can be his special car shirt...buy a few different ones at Goodwill and let him pick which one for which day of the week or whatever will work. My son is a HUGE fan of hooded t shirts and sweatshirts..he frequently pulls the hood up to block out extra stimuli when he can't handle it. And headphones and earplugs are a life saver too. It's possible the stress from the sensory overload of the harness may be lessened for him by distractions of things that reduce sensory input in other ways for him.

If all else fails, selling his old seats and saving up for a Recaro or a Britax combo seat (Frontier is going to have wider set shoulder straps than the Britax convertibles) may be the solution for now. Even the Graco Nautilus will have wider shoulder set shoulder straps AND it comes with strap covers.
GL!