It's an interesting idea to restrict props, but I don't think it would have much effect. I have found that the lighter electric props reduce vibration problems but don't necessarily improve performance. I use the standard "glow props" on my eSkyray, eClass 2, and sometimes eProfile.
It's still a solution looking for a problem that doesn't exist. All my glow engines have more power that all my electric motors in the corresponding classes. And I end up against the weight limit in all classes, so a bigger motor can't be added. If I could learn to build lighter airframes, I would add more batteries to extend the low speed times rather than going for a heavier motor.

Pete

I have been flying my Great Planes Combat RC ARF Spitfire lately with some electric power to compare several electric motors. The Spitfire has a 38" span and comes in at 3.5 lbs

I built the model with a OS-35FP originally and it has lots of power, maybe not enough for carrier but way more than I need for CL scale

Then I installed an E-Flite E10, with a 3S battery and an 11" APC electric prop...the performance let's say was lackluster at best, even from a CL scale point of view it was underpowered...but still wanted to know what the E10 could do. The max number of cells on the E10 per specification is an 3S.

Then I installed the E25 with the same electric APC prop and 3S battery, slight improvement but not much improvement. Remember the E25 is rated for a 3S or a 4S. This combination was still underpowered from a CL scale point of view, and way underpowered from a CL carrier point of view. This combination flew at cruise at about 2/3 power. So that combination was ruled out.

Then I installed a 4S battery on the E25, with the same prop and it had alot more power, way more than I would need for CL scale project I am building so that is what will be installed on that project. This combination flew at cruise at 1/3 to 1/2 power, at full power it had some speed, not enough for CL carrier but enough for CL scale.

What I have learned is that the power that you get out any given electric motor varies depending upon what battery and some degree what diameter of prop you use. My watt meter has been very handy to help determine what prop diameter is best suited for power or to lower the amp draw.

I think the battery we choose to use has a bigger affect on the power output than the prop that is selected.

Trying to nail down a electric motor that is equal to a .40 or .60 is diffiicult to do, there to too many variables that can change the power output such as battery voltage and prop diameter.

Fred Cronenwett

Comparing Electric to Glow engines is like comparing horse power ratings on auto engines.

Back in 1968 I bought an International Travelall rated at 192 HP to pull my travel trailer with.  At every Camp Ground we stopped at the discussion on Horse power came up.  At one place in Ohio a fellow was trying to impress everyone with his 300 HP Buick tow car.  When we started to leave the next morning, he passed me on the flat section of the exit road.  We then made a hard turn and started a climb up to the office.  Yep, Beep Beep and I passed him.  At the office he asked how my 192 HP could out pull his 300 HP.  I said it was easy to explain, he has 300 Shetlands and I have 192 Clidesdales.  I did not mention the 420 Pounds Foot of torque I had available.
Clancy