Ok, "ambush" dios are incredibly hard to pull off.
First off, as Sherman "ambush" setting is sprrising a target at 500m away (14m at 1/35 scale). A tiger "ambush" would be to surprise targets at 750-800m (21-22m) away.
You could cheat this, by using a town street intersection where the two vehicles might not see each other. However, tanks in town must have supporting infantry (as it keeps people from just dumping flamables into the engine intakes or otherwise boogering the tanks). Infantry will always look around corners (and through buildings) to protect their tank (it's their portable pillbox after all), so a surprise settting is going to want maybe a 100m, about 3m to scale.
The MGs on tanks are meant to provide suppressing (anti-infantry) fires out to 1500-2000m. Tankers get very nervous if anybody (other than friendly troops) get closer than 100-250m (bazooka/panzerfaust range).
Even at 1/72 scale, the distances are still large; this is why the wargamers use 1/1200, where 100m is only 83mm, or 1/2400 where it's 41.5mm to display tank-on-tank combat.
Now, a brief discourse on obstacles. You put tank traps obstacles where you do not want the tanks to go. As a tanker, you always reduce those obstacles, or avoid them entire (you typically have Corps of Engineers to sort such things out).
Barbed wire is only used to deter and detain infantry--tanks were invented to specifically defeat barbed wire. The only notice tankers will make of barbed wire is to be on the lookout for the infantry covering such obstacles watchig to see if the bad guys have breached that wire.
So, such things, especially in open country, always have a purpose.
You put out barbed wire to try to force the bad guys to go where you want them to, not where they want to go. You have to cover that wire, typically with an MG or two, in case the engineers or sappers try to break the barrier.
The same holds true of tank obstacles--you put them where you want the bad guy's tanks not to go. You put them in great big cleared swathes, so that any Engineers/Sappers sent out to destroy them would be real obvious, and very suseptable to MG fires from as far off as 1500-3000m away.
Thse things to not diorama well, other than one bit at a time
All that being said, the Russians really liked their Shermans (A3? the big diesel ones). They also made sure they had rather large red stars on them, too.