What I've found from experimenting with string tensions
TL;DR I don't lose power but sweetspot gets smaller.
I'll class myself as an intermediate club player at best. Very scrawny and not a particularly hard hitter but I can smash fast enough that I cannot get forward in time to get the block return.
I've recently collected 3 low end racquets of the same model, I'm not convinced they are entirely the same balance-wise but I'll assume they are for ease. I have tried the following strings, all +/- 1 each way, so in this cae 22m/24c = 23:
Micropower 66 @23lbsZymax 70 @23
Zymax 65 @23lbs
Zymax 62@ 22lbs. (only used for warmup, very unforgiving)
What I've noticed as I've increased tension/decreased string size is not that I have lacked power. In fact it has been the opposite, the crispness seems to let the shuttle fly off the racquet faster. The downside for me is that the sweetspot gets smaller. Such that if I mis-hit then I might as well not bother as the shuttle barely makes it to the net.
The increased feel is nice but the equivalent 1lb difference in the MP66 vs zymax65 makes the difference between a reactiction block to a smash go into or over the net, or a smash return making it to the back court rather than midcourt sitter. Any additional smash speed is negligable compared to the consitency of more shots making it over the net off a slight off-hit (backhand reaction to flick serves too). I can adjust either way for net shots so it depends which I get used to.
So I'm sticking at around 22lbs on the MP66, which I believe is stock for ashaway racquets (happy little coincidence). I think at this tension I shall only have +1 on the cross and string to allow for 1lb tension loss. TBC when I get my stringer to re-mesure my strings in situ now they have loosened up a bit.