This is not really a one size fits all question, meaning there is not one universally correct answer here. The right answer for you somewhat depends on your sailing style, and on the boat itself.
We each set our own threshold for when there is enough boat speed or wind to continue sailing and when it is time to crank up the noise maker. I hear people talk about having a ''3 knot rule'', meaning if they are not reading 3 knots on the knotmeter they crank the engine. For others, like myself, unless I have to be somewhere, I have an ''on the dial'' rule, which means as long as I am moving enough for the gauge to read, I will continue sailing and sometimes, even when the gauge is at zero, I will just plain sit and wait for the wind to fill back in. Neither approach is inherently better than the other. They are both simply a matter of taste and sailing styles. If you are closer to the 3 knot rule than you probably want a sail that is closer to 135-140 percent as you will probably not sail in a wind range that is light enough that a 150% genoa would be necessary. But if you are the ''on the gauge'' end of things then you will definitely want a 150% genoa.
The problem with a 150% genoa is that there is no such thing as a one sail inventory for a 150% genoa because a 150% genoa made out of conventional dacron and light enough cloth to be useful in really light winds, will be overpowered as winds begin to approach the high teens requiring a sail change.
Which then brings us to the matter of sail inventory. For some, there is only one headsail on board. It gets raised at the start of the season and lowered when the boat is hauled for the winter. Others, like myself, have an all purpose sail in the 135% to 140% range that they use most of the time but also have a blade for heavy air and a light 155% genoa for drifting days and have no compunction about choosing a particular sail for that day and putting it on the stay and even doing a sail change if things change throughout the day. Again it is a matter of sailing style.
This then brings us to the boat. To some extent you have chosen a boat that is less than ideal for where you are sailing. I would normally suggest a boat with an SA/D over 20 for your sailing venue carried in a more modern sail plan which typically would be proportioned with a large mainsail and smaller jib
. The Catalina 36 is a very dated design in terms of rig
proportions being just the opposite of that and carries and SA/D down in the 16-17 range. It also is a comapratively high drag hull for its displacement with moderately low stability for its drag. Therefore it is very dependent on having huge headsails in light air. This means that a 135% will be quite underpowered in lighter winds say under 10 or so knots. But because of the proportions of the rig
, this is still a relatively large sail. What that means is if the sail is made from light enough cloth to be useful in winds, under 8 or so knots, it will be too stretchy for winds much over 12 knots. That can be offset by going to a higher tech sail cloth and cutting pattern.
This is just the same process that I just went through. There are substantial differences in your boat and mine that effect the decision but in my case I just ordered an all purpose cruising sail for my boat. It is just below a 140% genoa. I had it made in mylar/kevlar laminate with a scrim one side and cut slightly on the flat side. I expect that sail to have a wind range from below 3 knots to around 20 knots. I never expect to sail with that sail partially rolled. The use of kevlar allowed the sail to be light enough to be used down to 3 knots of wind and still have the strength and low stretch that is required at the upper end of the wind range. I have a 95% low stretch jib
that I use on days where I expect the winds to remain above 12 to 15 knots, and I have a lightweight 155 genoa that I use on days that I expect to be below 8 knots or so. I can get away with that wide wind range on the all purpose sail because I have a very low drag boat, with comparatively high stability and an SA/D over 20 and the genoa represents a smaller percentage of my overall sail plan. I really don''t think that you have an option constructing a sail with that wide a wind range but if you prefer to sail at the lighter end of things then I would suggest that you are stuck going with a higher tech sail.
Good luck with the new boat,