Your Nordic 40 is close to a 'true' cutter with the mast at about 40% of LOA, sloops are at ~30% mast station / LOA. Makes a big difference in %LP and overlap.

So what Im saying that 'overlap' on such a design, and especially where the combined CE is 'in front' of the mast is 'incidental' of overall performance, except for 'light and flukey' winds where a BIG genoa is required.(nl)For 'boisterous' sailing (trade wind stuff), a simple 100% will usually be sufficient and won't be constantly overpowering. For lighter wind venues you can always 'fill in' the foretriangle by flying the staysail under the topsail .... but that requires some precise staysl set up and shaping to be 'effective'. For tech discussion of topsail/staysl combos go to arvelgentry.com ---> magazine articles ----> 'double headed rig" for the special sail shaping needed to optimize such a combo sail plan ... this is probably the only aerodynamically valid discussion ever presented for the staysail/topsail combo. ... Such is finicky, requires a knowledge of sail *shaping* but does solve the problem of attempting to 'furl' a 130-135% LP beyond 30% SA reduction (to 90%) and winding up with an unstable mishapened 'billowing pillow case' up front.

Coastal cruising with a 3 sail combo can involve a lot of tacking, the problem being the topsail usually fouling on the staysail or its forestay when tacking/gybing ... the shorter the LP of the topsail, the less 'fouling' ... and you 'can' employ a 'tracing line' which pulls the topsail clew 'through' between the forestay and headstay .... as was done routinely during the 1987 AC campaigns to get the huge genoas in between the headstay and the far forward 'baby stay' .... watch those 1987 videos if this is a possibility for you.

FWIW, most the boats that I see sailing in 'trade winds', including my own, seem to use either a blade or high cut 'yankee' as their headsail and over a staysail ... and only use a big genoa (sometimes free flying on its own integral luff wire) when in the light and flukes. Its far easier to 'power up' a small LP headsail to enable 'punching' into oncoming waves than attempt to do the same with a misshapened ratty-furled BIG genoa. Once you go beyond ~30% SA reduction by roller furling, you get 'nada' in proper sail shape.

The usage of a smaller LP will also permit 'inside the shrouds' attack angle .... for better VMG which can be important in long distances on long term tracks/tacks ... but as long as the headsail leech don't come in contact with the spreaders. The result is that you'll probably be able to set the headsails 'angle of attack' at closer to 10° rather than the typical minimum 12° as when flying a BIG LP that is sheeted outside the shrouds.

Of course, using an asymmetrical (especially on a spinnaker furling foil system - Facnor or 'roll-gen', etc.) for 'downwind' and short LP topsail for better 'pointing', to me, is the best all-around combo on a 'true' cutter. The functional problem with a BIG LP headsail on a (true) cutter rig is the total elasticity of the headstay when the sail is fully wind loaded and the resultant 'stretch' of that headstay results in a sidewards 'skid to leeward' instead of a 'point' ... hence my own preference for a short LP headsail (less headstay sag and/or less rig strain to compensate) when I have to point/tack for long distances in 'lively' conditions. With BIG genoas on cutters sometimes you have to crank down on the backstay + runners so damn hard to maintain luff shape and luff sag ... that you can easily exceed 30%+ rig tension ... the entry zone of 'yield' and rapid accumulation of 'metal fatigue'.

For these combos, I think, you also REALLY need to control the staysail with a clubfoot or hoyt-boom ... to prevent 'usual' undue twist when the clew is outboard, as without such the staysail will 'always' be flogging at the head, too over trimmed at the foot and only a teeny part of the mid panels actually 'drawing' properly (plus its vastly easier to 'blade-out' a staysail thats on a club-ft or hoyt-boom when in super-stink).

Thems my thoughts for the 3 sail confing of true cutter rigs ... and this isnt applicable to 'sloops' nor sloops that have added handkerchief staysails - 'slutter rigs'.