That's part of the problem. You should have felt a difference, even if it was very small.
Recognizing such performance differences may help you understand some of the dangers associated with higher performance canopies.
Good point about the OP's location and ordering the Lookma-RDS.
Although the Fluid Wings RDS attachment mechanism is a bit 'fiddly' (as aptly described by another poster here), it's still a good system. It just takes some practice. I removed / re-attached that thing 4-5 times at home before jumping it.
Although you said that you're not looking for an RDS, a custom sized removable slider may be your best option.
http://www.fluidwings.com/removable-slider