Same quiver I've been on for the past few seasons, with various add on options in 6m range…Blade/MoJo/Gator…
With a Blade 5.3, is a Blade 5.7 a logical next size up? No. (at least, not in many cases..)
Do I have some of the best sessions on Blade 5.7? Yes.
Would I like to be without a 5.7 even though I don’t need it ? No.
Is a Blade 5.7 on 86-90 Lt board one of my most rangy, versatile combos ? Yes.
Although the Blade 5.7 would end up delivering you some great sessions, from a $/quiver/range perspective Blade 5.3 + Gator 6.0 will likely be the winner, especially if your “6.0” riding is more freewave/freemove and less pure wave riding..
As you've enjoyed, Blades are very rangy as wavesails go, which is both an attribute but also a dilemma when it comes to picking sizes (both at purchase, and standing on the beach !) You can (should !!) make practical use of this versatility. Especially on a slightly floaty (more sail size tolerant tolerant) board like a 90Lt, 5.3 does really well extending down the low/er wind range - which reduces the absolute need to move to 5.7 earlier as the wind lightens.. Given the range of the Blades, taking a big/ger jump than 0.5m in that lighter sort of conditions (5.3-6.0m) is valid and practical (compared to same gap in say 4.2-4.7 conditions etc) BUT (and it’s a good one !!) if you’re often (might be THE key issue) in “5.7” conditions, the Blade 5.7 (esp coupled with a good 90Lt) is a rather magic/fun/satisfying combo, without going the full hog to the even larger 6.2. Or without sneaking by on the 5.3, which is often doable too! …
So, playing out the options ....
>> Blade 5.3+Blade 5.7 : Dream combo for a quiver with no practical restrictions. Consistent feel with smaller Blades and some great 5.7 sessions possible in “marginal 5.3 conditions”. Doesn’t extent quiver range as far down wind range as possible. Confusion at beach on “is it 5.3 or 5.7?”days (very real !!)
>> Blade 5.3+Gator 6.0 : Best combo of range without getting too big on the 6x size; Gator handling/feel softer than Blade, but this usually matters LEAST at the light/er wind end of the quiver and wind range (crossover to more freemove/freeride style riding). Less brain time required selecting rig at beach!
>> Blade 5.3 + 6.2; Doable, maybe better than you think(esp if you don’t mind a bit of power), will retain consistent “Blade” feel/handling thru quiver. May be a bit bigger than you dream about for super responsive handling/riding (when c/w 5.3 …and that elusive 5.7 !!) Less brain time required selecting rig at beach!
>> Blade 5.3 + S-1 5.9; Unless you’re looking for the super light response (freestyle/wave) advantage of the S-1 in lighter winds( a potential S-1 big +) , you will find the S-1 5.9 won’t give a significant amount more power than you experienced with Blade 5.7. S-1 sweetspot kicks in a bit more powered up (per size) than Blade.
Cheers ~ Ian
PS : I guess you waited around long enough to get in on the Forum, you deserved a good detailed reply !