Hi John,
Yes - though to be realistic, not all hams will understand that request. You need to send in the exact way you want the other station to send. The good operators will copy your style. The machine gun guys think it’s all about them and how fast they can send. Simply don’t give them contacts.
A further thought is to adjust the spacing gradually as suggested, down to the spacing that you find difficult. Say you go from double spacing (say 200%), to slightly less, say 150%. That may seem difficult. Try it for 5 minutes of reception. Then take the spacing back up a bit, say half way to the original, 170%. Do another 5 minutes at that spacing. It will seem easier.
Repeat that process and eventually you will find the standard spacing difficult but feasible. Return to the slightly wider spacing to regain confidence.
If you train yourself in this way, I think you will find this helps you by challenging your current ability, then reassuring you that the underlying capability is still there, then challenging you again. This principle is used in many learning scenarios.
73 Andrew VK1DA/VK2UH